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8 b P R IDRC-MR102eR

International Development Research Centre

MANUSCRIPT REPORT

Proceedings off a Workshop on Hydraulic Ram Pump (Hydram) Technology

s"^""**,

February 1986 ,Z4?.5-86ft-^

The International Development Research Centre is a public corporation created by the Parliament of Canada in 1970 to support research designed to adapt science and technology to the needs of developing countries. The Centre's activity is concentrated in five sectors: agriculture, food and nutri­tion sciences; health sciences; information sciences; social sciences; and communications. IDRC is financed solely by the Parliament of Canada; its policies, however, are set by an international Board of Governors. The Centre's headquarters are in Ottawa, Canada. Regional offices are located in Africa, Asia, Latin America, and the Middle East.

IDRC Manuscript Report

This series includes meeting documents, internal reports, and preliminary technical documents that may later form the basis of a formal publication. A Manuscript Report is given a small distribution to a highly specialized audience.

ISK z\gv

IDRC-MR102eR

PROCEEDINGS OF A WORKSHOP ON

HYDRAULIC RAM PUMP (HYDRAMl TECHNOLOGY

HELD AT ARUSHA, TANZANIA

MAY 29 - JUNE 1, 1984

ORGANIZERS:

CENTRE FOR AGRICULTURAL MECHANIZATION AND RURAL TECHNOLOGY (CAMARTEC) ARUSHA, TANZANIA

INTERNATIONAL DEVELOPMENT RESEARCH CENTRE (IDRC) OTTAWA, CANADA

Technical Editor: Eric J. Schiller

Material contained in this report is produced as submitted and has not been subjected to peer review or rigorous editing by IDRC Communications Division staff.

Mention of proprietary names does not constitute endorsement of the product and is given only for information.

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CONTENTS

FOREWORD A.B. Redekopp

WORKSHOP CONCLUSIONS AND RECOHHENDATIONS FOR ACTION

OPENING ADDRESS E.M. Nqaiza

INTRODUCTION

The Hydraulic Ram Pump (Hydram):

I ts History, Operatinq Characterist ics

and Potential Use E.J. Schiller

COUNTRY PAPERS

The Application of Hydram Pumps in Rural Water

Supply Schemes in Tanzania A. Mzee

The Use of Hydrams for Water Pumping in Tanzania D. Tulapona

The Hydraulic Ram Pump in Kenya Oyuko 0. Mbeche

The Hydraulic Ram Pump Technology

and Practice in Zambia

W.T. Weerakoon

V. Liyanage

MANUFACTURE, OPERATION AN) MAINTENANCE

Practical Aspects of Hydram Operation E.J. Schi l ler

The Manufacture of Hydrams S.S. Jandu

COMMUNITY PARTICIPATION

Community Participation and the Development of

Hydrams in Rural Water Schemes L.G. Msimbe

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CONTENTS (Continued) PAGE

Socio-economic Considerat ions i n Rural

Water Supply Development W. Baynit 66

RESEARCH NEEDS

The Theory and Desiqn o f the Automatic

Hydraul ic Ram Punp P.O. Kahanqire 71

Hydrau l i c Ram9 as Po ten t i a l Pumpinq

u n i t s for Rural Water Supply Schemes T. S.A. Mjwette and

i n Tanzania E. Th.P. Prot?en 100

LIST OF PARTICIPANTS 120

- ii -

FOREWORD

Providing adequate domestic water supplies for scattered rural populations poses a major

problem to many developing countries. Sparsely populated settlements cannot be easily served by

conventional piped water systems. In addition, the fuel and maintenance costs of operating a

conventional pumping system using diesel or gasoline engines are becoming prohibitive for many

developing countries. The hydraulic ram pump (hydram) is a simple technology that uses readily

available, renewable energy (a drop in water level of at least 1-2 meters in a flowing stream)

and has only two moving parts that can be manufactured and maintained by local personnel.

In the context of the International Drinking Water and Sanitation Decade, hydram technology

has not received the attention it deserves as a potentially useful component in national rural

water supply programs. Widely used in the 19th and the early 20th centuries, hydrams have been

installed throughout the world for water supply to villages and farms and for small scale

irrigation. In India, they supplied water to the famous fountains in front of the Taj Mahal. In

recent years the lack of emphasis placed on hydram technology by international agencies is due to

the preference of groundwater over surface water as a source of domestic water supplies.

However, in many regions of the world potable ground water is not readily available.

Until recently, research on operating characteristics and standardized designs for hydrams

have been lacking. Recently, research has been conducted by the University of Ottawa, the

University of Dar es Salaam and elsewhere on commercially-available hydrams as well as simple

locally-made models. These tests have determined the characteristics of some commercially-made

hydrams with the objective of designing simple locally-made pumps with comparable operating

characteristics.

This research needs to be continued in order to improve the design and durability of

locally-made hydrams. Locally-made pumps need to be field-tested to determine their performance

characteristics and durability under operating conditions in village settings. The social

acceptance of these pumping devices will need to be established to determine if and how these

devices fit into the existing social patterns of supplying water. These pumps will have to be

maintained by the local community which will involve close cooperation, and community

participation of local users. Socio-cultural studies will need to be conducted in this

connection. Having developed a locally-made, economical, durable and socially acceptable pump,

the final step will be to assist in the planning of an indigenous production capacity.

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IDRC recently sponsored a workshop held in Arusha, Tanzania to address the above issues and

to look carefully at various aspects of the implementation of these systems at the village level

within the context of East Africa. The workshop also included a vis i t to Jandu Plumbers (Arusha)

who are manufacturers of hydrams and field t r ips to observe pumps installed in the vicinity of

Arusha. The workshop provided an opportunity for participants to share information on hydram

technology and plan for future development of th i s technology. Research pr ior i t ies for Africa

were discussed and research protocols prepared.

Acknowledgement8

Mr. D. Tulapona of CAMARTEC and Mr. A. Redekopp of IDRC, served as administrative organizers

for th i s workshop. The following assisted in the research proposal writing process at the end of

the workshop. A. Redekopp and J . Chauvin, IDRC, E.J. Schiller, University of Ottawa, E. Protzen,

University of Dar es Salaam, and P. Kahangire of the Water Department of Uganda. Finally, E.J.

Schiller served as technical editor in the publication of the proceedings.

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WORKSHOP CONCLUSIONS AND RECOWPPATIONS FOR ACTION

Conclusions

1. Conventional pumping methods are becoming more and more d i f f i c u l t to maintain in developing

countr ies. The need to use renewable energy technologies in rura l areas has increased. The

use of the hydraulic ram pump (hydram) i s an example.

2. One of the problems with hydram technology i s that a major i ty of potent ial users are not

aware of these pumping devices. Therefore, promotion and dissemination of information of

hydram technology should be increased. Hydrams are commercially available and technical

drawings of working devices already ex i s t . These must be made available to users. Even

more detailed technical information must be generated and disseminated.

3. Training of users, water engineers and technicians in i n s t a l l a t i o n , operation and

maintenance should be stressed.

4 . I t seems that at present a predominant problem i s that most durable hydrams are

proh ib i t ive ly expensive. There i s a need to develop low cost , loca l ly manufactured

l ightweight versions.

5. The f i r s t step in such a development i s a good evaluation of exist ing analyt ical models as a

design a id . A l l interested groups should be involved in t h i s process.

6. Each country should ident i fy a l l potent ial hydram s i tes including hydrological ,

topographical, geographical, water-quality and population data.

7. Each country should make a thorough survey of exist ing operating and non-operating hydrams

for technical and sociological information.

8. A designed l ightweight version should be insta l led in selected s i tes and f ie ld - tes ted . To

f a c i l i t a t e t h i s , complete operating character ist ics must be developed with the aid of a

computerized analyt ica l model. Field tests could indicate the need for future design and

manufacturing improvements.

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9. There is a need to interest manufacturers in the l ightweight , low-cost version and improve

f isca l benefi ts by more cooperation between users, design engineers and manufacturers.

10. Though the hydram is a low maintenance device, i t i s s t i l l important to plan for adequate

maintenance and spare parts supplies. When schemes are commissioned benef ic iar ies should

feel responsible to protect , operate and maintain the system.

11. Lack of health education makes the comminity less aware of the importance of improved water

supply systems. Also cu l tu ra l be l ie fs in some instances may not favour the use of hydrams.

Run—nidations for Action

1. Countries planning to promote hydram technology should begin with a thorough survey and

inventory of potential s i tes and exist ing i ns ta l l a t i ons . This should include a study of the

technical , social and economic potent ial of hydrants.

2. A common East African computerized hydram model should be completed immediately t o :

a) generate operating character ist ics of a l l exist ing hydrams; and

b) to assist i n the design of new low-cost versions of the hydram.

3. Local manufacture of low-cost, su f f i c i en t l y durable hydrams should be undertaken.

4 . The new versions of the hydram should be ins ta l led and f i e ld - tes ted .

5. Health education programmes should be implemented to improve water use habi ts.

6. Hydram operator-caretakers should be chosen from among the v i l lages and properly t ra ined.

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Research Needs

Given the above recommendations, there is a need to conduct research on the technical,

social and economic potential of hydrams. Demonstration schemes should also be set up to assess

their technical performance and social acceptability, and to train and monitor the effectiveness

of village level operator caretakers.

Some delegates at the Workshop on Hydram Technology

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OPENING ADDRESS

E.H. Ngaiza

I take t h i s opportunity to welcome part ic ipants of th i s Workshop to Tanzania and Arusha in

pa r t i cu la r . I t i s my hope that you had a pleasant t r i p here. Welcome to Tanzania and please

feel at home during your stay.

I would l i k e , at t h i s juncture, to thank IDRC for convening th i s Workshop in Tanzania and

especial ly i n Arusha where CAMARTEC is located. I feel we are very much honoured to have

CAMARTEC as co-organizers of the Workshop. We w i l l do our best to make the Workshop a success.

Also, we w i l l do our best to make your stay as comfortable as possible.

The theme of the Workshop i9 of great importance. You a l l know the current socio-economic

problems facing many communities of the developing countr ies. This has prompted many

researchers, social and natural sc ien t i s ts , to explore various a l ternat ive means of solving our

development problems. Among the socio-economic problems, which i s of great importance to our

development, i s water supply. The question of water supply and sani tat ion i s c r u c i a l . We need

water for domestic use, for i r r i g a t i o n , and for producing power. This Workshop focuses on the

use of water energy to supply water, that i s , the hydraulic ram technology.

The use of hydraulic rams to pump water for domestic use and i r r i g a t i o n i s not as widespread

as the use of other water l i f t i n g devices. Many factors are involved but I w i l l make reference

to a few. You w i l l have time during the sessions to discuss them in d e t a i l . Technical and

social barr iers affect the widespread use of hydraulic rams. Technically, in each country there

have been engineering design problems. In Tanzania, for example, the manufacturers of hydraulic

rams are Jandu Plumbers L td . of Arusha who have been working on hydraulic rams in East Afr ica for

the las t f i f t y years. The engineering design in use in Tanzania has not changed much and has not

been given serious study by experts other than those working with Jandu Plumbers Ltd. I t should

be possible to modify the design to make i t more a t t rac t i ve and less cost ly .

Socia l ly , the widespread use of the hydraulic rams i s affected by the di f ferent ways of

introducing the technology to the end users. A lack of exposure and knowledge of the technology

to the users and potent ial manufacturers i s one of the major fac tors . The end-users need to be

aware of the advantages of using hydraulic rams for domestic and farm water supply. Costs of the

pumps should be wi th in the l i m i t of the user's purchasing power.

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I hope the participants will have time to consider the problems mentioned above and will

finally come out with well considered projects for implementation.

I, therefore, declare this Workshop open and wish you all the best.

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THE HYDRAULIC RAH PUMP (HYDRAM):

ITS HISTORY, OPERATING CHARACTERISTICS AND POTENTIAL USAGE

E . J . Sch i l l e r

ABSTRACT

The hydram i s introduced as one of a series of renewable energy technologies in ru ra l water

supply. The operating pr incip les of the hydram are out l ined. A short history of hydram

development i s given. Present day usage i s surveyed. The main operating character ist ics of

hydrams are described. Present and future research ac t i v i t i es are noted.

INTRODUCTION

The hydraulic ram pump (hydram) is one of a group of renewable energy technologies that use

the energy of the sun or an energy from that i s d i r e c t l y derived from the a i r . In the case of

the hydram, the energy source i s a small drop in elevation in a flowing stream.

The hydram shares several character ist ics in common with other renewable energy technologies

used in the water supply sector such as wind power pumping, hand pumps, stream-driven turbines and

solar driven devices. Many of these devices have the capabi l i ty of being manufactured loca l l y

using local s k i l l s and materials. These technologies are re la t i ve l y simple compared to foss i l

fuel devices that require heat resistant metals, and e lec t r i ca l devices that require an

e lec t r i ca l network or an e lec t r i ca l generator. Most renewable energy devices can be operated

independently with minimal spare parts needed for regular maintenance. They can therefore

function reasonably well even i f the transportat ion and communications network in a country i s

not highly developed. This factor makes these devices well suited to rural populations that are

widely scattered.

THE OPERATION OF THE HYDRAM

The hydram makes use of the sudden stoppage of flow in a pipe to create a high pressure

surge. This i s commonly known as water hammer. This high pressure wave i s u t i l i zed to pump

12 -

some of the water to a higher elevation or to a locat ion that is displaced horizontal ly from the

pump. I f the flow in an ine last ic pipe i s stopped instantaneously, the theoret ica l pressure r i se

that can be obtained i s

dH = - ^ £

g

where 4 H = pressure r ise (m)

V = the o r ig ina l veloci ty in the pipe (m/s)

c = the speed of an acoustic wave in the f l u i d (m/s)

g = acceleration due to gravi ty (9 .8 m/s )

The above represents the maximum pressure r ise possible. The actual value w i l l be lower

since a l l pipes have some e l a s t i c i t y , and i t i s impossible to instantaneously stop the flow i n a

pipe.

To make use of the above p r i n c i p l e , a typical hydrant i s constructed as in the diagram below.

STRAINER

/ /

HEADER ^ \ T A N K

x t

/ / * / / ^UJ

' 0

DELIVERY VALVE

1

Hd

L

AIR VALVE

Figure 1 : A TYPICAL ARRANGEMENT IN A HYDRAM INSTALLATION

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The hydram i s simple in construction. I t contains only two moving parts, the waste valve

and the del ivery valve. There are two pipes, the drive pipe leading the water into the pump and

the del ivery pipe d i rect ing the water to the place where i t w i l l be stored and subsequently

used. An ai r chamber and ai r valve are the other two components i n the body of the hydram.

The pumping cycle of the hydram begins with the waste valve open. In a natural stream, the

supply is taken from upstream, perhaps from a small dam created in the stream. Because of the

head created, water accelerates in the drive pipe and leaves through the waste valve. The

equation for t h i s acceleration i s well known in f l u i d mechanics and can be given as,

H - M_V^ = J^jW (1) 2g g dt

where M V* expresses the to ta l f i c t i on losses

2g

L = length of the dr ive

and V = veloci ty of flow in the pipe

t = time

Eventually t h i s flow w i l l accelerate enough to begin to close the waste valve. This occurs

when the drag and pressure forces in the water equal the weight of the waste valve. Tor the

purpose of analysis, the force on the valve can be represented as a drag force, F^, given by the

equation.

F d a C d \ y V i 3 2g (2)

where Ay = cross sectional area of the waste valve

•y = specif ic weight of water

C = drag coef f ic ient of the waste valve

For optimum operation, the closing of the valve should be as fast as possible. On t h i s

basis alone a l i gh t valve with a short stroke length i s best. However, i f a valve i s too l i g h t

i t w i l l not open soon enouqh later in the cycle; on the other hand, i f the stroke is too shor t ,

not enough water can escape out of the waste valve opening, t h i s l im i t i ng pipe veloc i t ies and

thus reducing water hammer pressures. The proper design of the waste valve must therefore be an

optimal balance between a l l the various factors involved.

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The sudden closing of the waste valve creates a high pressure surge as explained

previously. This surge is great enough to open the delivery valve and release some of the water

into the delivery pipe. With the release of this water, the high pressure surge in the drive

pipe collapses and slight negative pressure recoil occurs.

Three significant things occur when the pressure wave collapses in the drive pipe. Firstly,

the delivery valve closes thus ending the pressure surge that is sent to the delivery pipe. The

air chamber cushions the pressure pulse so that a reasonably continuous flow is sent to the

delivery pipe. In this cushioning process the air-water interface is continually agitated and

moving. This tends to dissolve the air into the water. The air supply is replenished by a

second phenomenon that occurs at this time. The slight negative pressure pulse enables air to be

sucked into the air valve. Later in the delivery phase, this air passes the delivery valve and

goes to the air chamber. This air valve can be a one-way air valve or it can be a .very small

drilled hole (1mm) which releases water during the pressure surge and sucks in air during the

collapse of the pressure wave.

The third event that occurs at the end of the pressure pumping phase is that the waste valve

opens, either by the action of its own weight or by means of an activating spring. When thi9

happens, the flow is ready to begin again. The hydram cycle thus repeats itself continually, at

a frequency between 40 to 200 beats per minute. The fact that this pump operates 24 hours per

day with only minimal maintenance is one of its main advantages.

THE HISTORY OF THE HYDRAM

The history of the hydram goes back more than 200 years. We are, therefore, not discussing

a new technology, but an old technology that is experiencing a renaissance, brought about by the

fossil fuel crisis and energy shortages in general. The hydram shares this characteristic with

other renewable energy technologies such as windmills, handpumps and various solar devices.

The first person apparently to try to use a water hammer pressure in a pipe for pumping was

John Whitehurst, an Englishman in 1775. His hydram was not automatic, but the operation was

controlled manually by opening and closing a stop-cock. Although Whitehurst installed a few of

these devices, the apparatus was difficult to operate and did not become very popular.

The inventor of the automatic hydram as we know it today was a Frenchman, Joseph

Montgolfier, who patented the device in 1797. He introducted the waste valve that opened and

closed automatically and gave us the name "hydraulic ram" pump. This creative Frenchman also

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invented the hot a i r bal loon, which in the French language is named af ter him. However, the

hydram of Montgolfier suffered from a defect . The a i r in his a i r chamber eventual ly dissolved,

causing intense banging in the mechanism which was especial ly serious with the larger models. I t

was his son, P ier re Francois Montgolf ier , who designed the a i r or sn i f t e r valve to introduce a i r

into the a i r chamber. This made possible the design and construction of large hydrams and made

i t possible to pump water to higher del ivery heads.

During the nineteenth century there was intense a c t i v i t y in the design and construction of

hydrams often on a very large scale. This a c t i v i t y , which or iginated in Europe, including

B r i t a i n , spread to North America. Very large hydrams are reported in the U.S.A. from the end of

the nineteenth century (Mead, 1901) with a 10-inch (250mm) diameter intake pipe capable of

pumping 870 L/min. to a height of 25m in I l l i n o i s and an even larger 12-inch (300mm) diameter

hydran in Seatt le which i s reported to have pumped 1700 L/min. to a height of 43m (Carver, 1918;

Mead, 1933). These hydrams were enormous in size and the drive pipe walls had to be made very

th ick to withstand the water hammer pressures.

With the advent of steam power, fossi l fuel driven engines and e l e c t r i f i c a t i o n , t h i s period

of hydram manufacture began to dec l ine . Although same few companies have continued to

manufacture hydrams, i t i s only in the last two decades that a renewed interest in hydrams has

occurred as the world-wide energy shortage has begun to change our energy pat terns. Companies

are now developing smal ler , l igh ter hydrams sui table for use in scattered areas.

A l i s t of present day manufacturers and d is t r ibu te rs in North America and England i s as

fo l lows:

- Berry H i l l Limited (Davey hydrams)

75 Bur well Road

S t . Thomas, Ontario N5P 3R5

CANADA

- Rife Hydraulic Engine Manufacturing Company (Ri fe hydrams)

132 Main Street

Andover, New Jersey 07821

USA

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- C.W. Pipe Inc. (Fleming hydro-ram)

P.O. Box 698

Amherst, Virginia 24521

USA

- John Blake Limited (Blake hydrams)

Hydraulic Engineers

P.O. Box 43

Royal Works, Lancashire

ENGLAND BBS 5LP

- Green and Carter L td . (Vulcan hydram)

Vulcan Works

Winchester

ENGLAND

PRESENT DAY USAGE OF HYDRAMS

The hydram is employed in many scattered areas of the world, although not in great numbers.

They are s t i l l employed throughout Europe, England North America although the i r period of peak

usage there dates back to the last century. The famous fountains of India's Taj Mahal were

powered by hydrams and they are used in rura l areas in Russia.

However, the main area of interest for present-day hydram applicat ion i s in the countries of

the developing world. They are used throughout East A f r i ca . They are most appropriate with

streams in h i l l y te r ra ins , and i t i s i n such regions where hydrams tend to be concentrated.

I t i s the role of women to carry water i n most developing countr ies, and carrying water i n

h i l l y country i s especially arduous. Therefore, women have the most to gain by the development

of pumping technology (Madeley, 1981).

HYDRAM OPERATING CHARACTERISTICS

I t is standard engineering practice to depict the performance of water pumps by giving the i r

operating character is t ics. For the hydram there are two sets of character ist ic curves that are

especially useful .

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The f i r s t i s a plot of head ra t io (h/H) versus flow ra t i o (O/Qw). For def in i t ions of the

symbols see Figure 1 . This i s a dimensionless curve that i l l u s t r a t es hydram performance for a

given supply head. For high head rat ios the curves tend to be simi lar but some divergence i s

noted for the lower head ra t i os . Kahangire (1984) found th i s trend to be true for most of the

hydram8 that he tested.

In general, these curves show that hydrams can pump much water for low l i f t s , but as the

l i f t increases the amount of water decreases.

Another useful curve i s the curve of e f f i c iency , defined as

Q.h

Qw.H

as a function of del ivery f low. This t e l l s how e f f i c i e n t l y the hydram pumps the water. This i s

important where the dr iv ing source of water i s l imi ted and waste water must be kept to a

minimum. Where the stream flow i s abundant, the ef f ic iency i s not so important. However,

ef f ic iency readings give us a good indicat ion of the hydraulic performance of the hydram. Hiqh

ef f ic iency machines have low f r i c t i o n losses are hydraul ica l ly well designed. For a given head

(H), the ef f ic iency curves of d i f ferent hydrams w i l l indicate which type of hydram i s most

suitable for the par t icu lar se t t i ng . Figure 3 shows the ef f ic iency curves for various hydrams

operating with a head of 2m.

- 18 -

0.32 0.40 FLOW RATIO

Figure 2 : DAVY HYDRAM fCAD RATIO VS FLOW RATIO

- 19 -

o o

1.00 2 .00 DELIVERY

3.00 4.00 5'. FLOW (L/MINUTE)

6.00

Figure 3: EFFICIENCY VS DELIVERY FLOW

COMPUTER MODELLING OF THE HYDRAM

The purpose of computer modelling is to allow designers to predict the influence of given

factors on hydram performance. Kahangire (1984) has developed a computer model for hydrams which

has.been produced in basic computer language for micro-computers. Data describing the proposed

site together with hydram dimensions and friction loss characteristics are inputted into the

programs. Operating characteristic curves are then produced by the computer program. Figures 4

and 5 are curves plotted by the computer model. They indicate the kinds of analysis that can be

done with the use of this computer model. Figure 4 can be useful in assisting the design of more

efficient waste values and Figure 5 can be used to help install hydrams in different sites with

different heads available.

- 20 -

Figure A: EFFECT OF FRICTION Figure 5: EFFECT OF SUPPLY HEM) ON HEM) LOSS OF THE HYDRAM EFFICIENCY

HASTE VM.VE ON PUMP CAPACITY

AREAS OF HYDRAM INVESTIGATION AND DEVELOPMENT

Because of increased interest i n th i s renewable energy technology, there are a number of

centres where research has been done or i s s t i l l continuing i n hydram pumps.

Research ac t i v i t y has been reported in Indonesia (Hanafie and de Longh, 1979) and the

Technische Hogfeschool Eindhoven and the Delft Hydraulic Laboratories, both i n Holland. The

Intermediate Technology Development Group (ITDG) in England has published books in t h i s area

(Watt, 1978). In the USA, Volunteers in Technical Assistance has published hydram manuals

(Kindel 1975; Inversen, 1979) and the Peace Corps has published a "Training Manual in Conducting

a Workshop in the Design, Construction, Operation Maintenance and Repair of Hydrams" 1981.

The University of Ottawa has completed extensive tests on hydrams in order to (1) determine

the operating character ist ics of commercial hydrams, (2) compare these operating character ist ics

with those of a locally-made hydram, and (J) suggest design modif ications for locally-made

hydrams.

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F ina l l y , i n Tanzania, the Ins t i tu te for Product iv i ty Innovation at the University of Dar es

Salaam is conducting tests to model hydrant performance with a goal to improve present designs.

FUTURE HYDRAM DEVELOPICNT

Three main areas for future research are i d e n t i f i e d :

1) Existing hydram designs, some of which are very durable have a price that makes i t

d i f f i c u l t to be purchased in developing counties. Economic studies should be done to

determine true hydram costs, spread over the l i fe t ime of the hydram.

2) Low priced hydram models need to be designed, manufactured and f i e ld - tes ted .

3) An improved computerized hydram model needs to be developed and produced for computation

with microcomputers. This would enable rapid comparisons to be made of exist ing

hydrants. I t would also be a useful tool in future design modif icat ions.

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REFERENCES

Behrends, F.G. (1926) "Use o f the Hydrau l i c Ran". The Farm Water Supply (Part i i ) . Corne l l

Extension B u l l e t i n 145, New York Sta te Col lege o f A g r i c u l t u r e , Corne l l U n i v e r s i t y .

Cabine, Charles (1937) "Joseph de Mon tgo l f i e r et l e B e l i e r Hydrau l i que" . Proceedings,

I n s t i t u t i o n o f C i v i l Engineers, London.

Carver , T.H. (1918) "Hyd rau l i c Ram Shows 915S E f f i c i e n c y " . Engineer ing News Record, V o l . 80 ,

No. 2 1 , New York.

Dickenson, H.W. (1937) " E a r l y Years o f the Hydrau l i c Ram". Proceedings o f the I n s t i t u t i o n

o f C i v i l Engineers, January, pp. 73-83, London.

Hana f ie , J . and DeLongh, H. (1979) "Tekno log i Pompa H i d r a u l i k Ram". I n s t i t u t Teknologi

Band ung.

I n v e r s i n , A.R. (1979) "Hydrau l i c Ram f o r T rop ica l C l i m a t e s " . V i t a P u b l i c a t i o n , V i t a , Mt.

R a i n i e r , Mary land.

I ve rsen , H.W. (1975) "An Ana lys is o f the Hydrau l ic Ram". Journal of F l u i d s Eng ineer ing ,

ASME No. 75-FE-F, T ransac t ions . New York, ASME, June, pp. 191-196.

Kahangire, P.O. (1984) "An Exper imental I n v e s t i g a t i o n and Design o f Hydrau l ic Ram Pumps",

M.A.Sc. Thes is , C i v i l Engineer ing Department, U n i v e r s i t y o f Ottawa.

K i n d e l , E.W. (1975) . A Hydrau l i c Ram for V i l l age Use. A V i t a P u b l i c a t i o n , Mt. R a i n i e r ,

Mary land.

K r o l , J . (1952) "The Automatic Hydrau l ic Ram". Proceedings o f the I n s t i t u t i o n o f Mechanical

Engineers, V o l . 165, pp. 53-65.

Lans fo rd , W.M. and Dugan, W.G. (1941) "An A n a l y t i c a l and Exper imental Study o f the Hydrau l i c

Ram". B u l l e t i n No. 326, V o l . 38. Un i ve r s i t y o f I l l i n o i s Engineer ing Exper imental S t a t i o n .

Madeley, J . (1981) "Ram Pumps and Kenyan Women's Water T r e k " , World Water, London, October ,

pp. 51-52.

- 23 -

13. Mead, D.W. (1933) "The Hydraulic Ram". Hydraulic Machinery. New York: pp. 358-383.

14. Mead, D.W. (1901) "A Large Hydraulic Ram". The Engineering Record, Vol. 44, No. 8, New

York: August.

15. Peace Corps (1981). A Training Manual in Conducting a Workshop in the Design, Construction,

Operation, Maintenance and Repair of Hydrams.

16. Protzen, E.P. (1980) "A Proposal for Simple Performance Prediction of the Hydraulic Ram".

(Unpublished Reserch results), Institute for Production Innovation. University of Dar es

Salaam, Dar es Salaam.

17. Schiller, E.J. (1982) "Development of a Locally Made Hydraulic Ram Pump". ENERGEX '82

Conference Proceedings, Solar Energy Society of Canada. August, pp. 503-506.

18. Schiller, E.J. (1982) "Renewable Energy Pumping from Rivers and Stream". Water Supply and

Sanitation for Developing Countries. Michigan: Ann Arbor Science Publishers, pp. 53-64.

19. Silver, Mitchell (1977), Use of Hydraulic Rams in Nepal. A guide to Manufacturing and

Installation, Kathumandu, Nepal: UNICEF, September.

20. Smallman, W.S. (1934) "The Hydraulic Ram, Its Construction and Use". Newcastle, Australia,

Newcastle Division of the Engineers of Australia, paper No. 569, pp. 357-360.

21. Stevens-Guille, P.E. (1970) "An Innovation in Water Ram Pumps for Domestic and Irrigation

Use". London, Appropriate Technology, Vol. 5, No. 1.

22. Stevens-Guille, P.D. (1977) "How to Make and Install a Low-cost Water Ram Pump for Domestic

and Irrigation Use". Cape Town: Department of Mechanical Engineering, University of Cape

Town, August.

23. Watt, S.8. (1978) A Manual on the Hydraulic Ram for Pumping Water. London, Intermediate

Technology Limited.

- 24 -

THE APPLICATION OF HYDRAM PUMPS IN RURAL

WATER SUPPLY SCHEMES IN TANZANIA

A. Mzee

ABSTRACT

A survey of Tanzania's water development goals i s given, together with the mix o f

technologies presently used in the water supply sector. A preliminary survey of hydram potential

i s advocated, together with a f i e l d test ing program. The proposed program should determine i n

deta i l the potential for hydram development in Tanzania.

INTRODUCTION

The Tanzanian twenty-year (1971-1991) long-term water supply goals, i n accordance with UN

Water Supply and Sanitation Decade resolut ions, plans to supply everyone with c lean, potable and

adequate water within easy reach by 1991.

A major constraint in the implementation of the Rural Water Supply Programme i s a lack o f

adequate f inancial resources for construction of new projects as well as operation and

maintenance of the completed schemes. With the high cost of fuels and equipment, i t i s of utmost

importance to deploy technologies with less energy demand that can u t i l i z e available renewable

energy resources. I t i s equally important to fabricate and maintain locally-made appropriate

devices used in harnessing such resources. At present, most of water pumps in rural areas are

run on d iesel . These pumps and engines need a constant supply of f u e l , sk i l l ed manpower, spares,

equipment and transportat ion for the i r maintenance. These are scarce and cost ly commodities. To

reduce dependency on these items, the need for a l ternat ive methods i s desirable.

A water sector review in 1976 showed that water supply systems were being undertaken i n

accordance with the following technology mix:

- 25 -

TECHNOLOGY USED AND UNIT COSTS OF EXISTING SYSTEMS (1976)

TYPE OF SUPPLY

Surface gravity

Surface diesel powered pump

Surface hydram pump Surface windmil pumped

Borehole diesel power pumped

Borehole windmill pumped

Shallow wells hand pumped

% TOTAL POPULATION

SERVED

28 41 * * 22 * 9

PER CAPITA

DESIGN

POPULATION

230 250 * * 300 •» 80

COST (Shs) PRESENT

POPULATION

345 375 * • 450 » 120

* Negligible population

Cost analysis showed that it was necessary to adapt least cost, simple technology options if

the programme goals were to be achieved. Further, the Government declared its intention to go

for options such as wood/bamboo, windmills, hydraulic rams, etc. Reporting to the party (CCM)

conference in 1980 the Ministry of Water and Energy stated, "It is the Government's intention to

encourage the use of hydraulic rams whenever it is difficult to convey water by gravity.

Batteries of rams can be installed instead of diesel engines". The report was adopted by the

party. Hitherto, no serious consideration has been given to the field of hydrams in the

program. The hydram potential has not been determined, although it is believed there is

significant potential in Kilimanjaro, Tanga, Iringa, Mbeya, Rukwa, Ruvuma, Morogoro, Kigoma,

Kagera and other hilly regions where perennial rivers are abundant. Further, the knowledge

available with regard to the development and operation of the schemes is too scarce to enable

provision of national guidelines. In order to popularize the option for wide-scale application,

preliminary knowledge on limitations, cost implication, acceptability, adaptability, reliability

and maintainability is necessary. This would assist in making sound decisions on the application

of hydrams. To avoid an ad hoc approach, the following research needs are considered necessary.

PRELIMINARY SURVEY

The main objective of the survey is to collect and compile relevant hydrolocical and

topographical data in order to determine water flows and topographic levels. This would form the

basis of selecting suitable sites for hydram schemes. Water Master Plan Studies already carried

out in many regions would be the main source of information.

- 26 -

A survey of village patterns including locations, s ize , population and water demand will be

carried out to assess areas of use and relevant size of hydram project. This will help in

knowing the extent to which the hydram technology will be used in comparison with other

technology mixes. An idea of the most common size of a hydram pump likely obtained from such

information would further assist in fixing standards for the hydram designs.

Upon selection of suitable project locations further preliminary surveys will be undertaken

to investigate the economic factors, existing social conditions, att i tude of villagers towards

scheme ownership, participation in construction and maintenance of the hydram water supply

system.

ORGANIZATION OF THE HYDRAM FIELD TESTING

Baaed on the findings of the preliminary survey, hydram schemes will be constructed at

selected villages under normal project implementation procedures. Guided by the input from the

vi l lagers , the method of implementation shall be decided with emphasis of beneficiaries '

participation, self-help labour or otherwise. The instal la t ion of hydrants shall be done by

project personnel who would continue to inspect and monitor i t s performance.

During the course of the hydram operation, performance t e s t s shall be carried out. This

will include collection of important information and taking measurements to verify design

parameters and to assess durabili ty of hydrants under field conditions. The behaviour of various

components of the system such as valves, springs, s i r chambers and pipe f i t t ings shall be

monitored. An analysis of hydram parts at the end of the project shall be necessary. Parameters

such as volumetric efficiency, water head, water output, frequency of use, stream flows shall be

recorded. Suitable and reasonably accurate devices shall be used in taking measurements.

Csreful consideration shall be given to the location of the schemes. For ease and

convenience of construction and maintenance, inspection and monitoring the accessibility to the

s i te will be important. The scheme construction shall be as simple as possible. Locally

available materials such as burnt mud bricks or wood staves shall be used to construct the head

pond and supply reservoirs. The piping material shall be determined by the drive, delivery and

supply heads available for each scheme. For the purpose of comparing operating character is t ics ,

i t is proposed to ins ta l l both locally and commercially made hydraulic ram pumps.

- 27 -

CONCLUSION

In view of the high cost of fuels and lubricants, difficulties in transportation, shortage

of skilled manpower and materials to maintain diesel engines, it is imperative to encourage use

of indigenous renewable energy resources such as hydraulic ram pumps. The research proposed here

aims at understanding the suitability of such applications in Tanzania. At the end of the

research, answers to the following questions should be found:

1. Are hydraulic ram pump applications technically, economically and socially acceptable?

2. What is the approximate cost and size of a village hydram scheme?

3. What would be the most common size of a hydram to be used in the water programme?

4. What is the unit cost of water production using hydrams as an optional technology?

5. To what extent can hydrams be used in the water programme?

6. What is the extent of energy saving using this option?

7. What are the weak parts of the hydraulic ram as a pumping device?

8. What level of reliability can be expected from a village hydram scheme?

9. How comparable in performance and economy are locally fabricated hydrams?

TO. To what extent should beneficiaries' participation be expected in construction, operation

and maintenance of a hydraulic ram system?

11. Who should be encouraged to own a hydraulic ram scheme - a public institution or a private

undertaking?

Finally, it is hoped that the existence of such preliminary knowledge will assist planners,

engineers and financiers in making sound decisions on the use of hydraulic ram pumping schemes in

the development of water schemes in the country.

- 28 -

THE USE OF HYDRAMS FOR WATER PUMPING IN TANZANIA

by 0 . Tulapona

ABSTRACT

The need for more renewable energy technologies in the rura l water supply sector i s

h ighl ighted. Some design aspects are discussed and the outlook for local manufacture i s

surveyed.

INTRODUCTION

In Tanzania, as in most developing countr ies, the problem of water supply i s not only i t s

general scarci ty, but also where i t i s p l e n t i f u l there i s the problem of gett ing i t to where i t

i s needed. In p r inc ip le , there i s water everywhere in Tanzania even i n the dr ier central

plateau. The success of the Shallow Nells Project in the Lake Zone and Morogoro Region proves

the point . The southern and northern highlands are endowed with fa8t flowing r ivers which have

enough water a l l the year round. The great lakes which almost surround hal f of the country and

smaller lakes scattered throughout the country are a l l cold water sources.

In general, Tanzania's water sources can be u t i l i zed for domestic and i r r i ga t i on purposes.

The saline water of the sea has been l e f t out of t h i s discussion purposely as i t s use for

domestic or i r r i ga t i on purposes requires technologies not included in th i s Workshop. The three

forms in «hich cold water occurs are: running water ( r i v e r s , springs, streams), stagnant water

( lakes, dams, ponds) and underground water. Being on the surface, the f i r s t two forms are easy

to tap and ready for use, provided health precautions are observed. Underground water, on the

other hand, has to be extracted by digging and d r i l l i n g wells to bring water to the surface. The

water table varies from place to place thus making the task of l i f t i n g the water even more

d i f f i c u l t .

There are a number of wa te r - l i f t i ng devices with varying outputs and uses. There are the

pumps which range from the simple low-output hand pumps to the high-speed high-capacity

centr i fugal pumps. Others include Persian wheels, Archimedean screws, axial flow pumps and

hydraulic rams. Of course, there are also shadoofs, windlass and p a i l , t readmi l l and others less

fami l iar in th is country.

- 29 -

A l l these devices require energy to operate them. The energy required varies according to

the type of device and the amount of water to be l i f t e d . The low-speed, low-output devices such

aa handpumps, Persian wheels, shadoofs, windlass and p a i l , t readmil l and Archimedean screw a l l

u t i l i z e human or animal power. Windmills are also used to drive pumps which l i f t water from bore

holes and deep wel ls. The well-known handpump and the windlass and pai l are pr imari ly for

l i f t i n g water for domestic use and stock watering only. Due to the i r low output, they are not

suitable for l i f t i n g water for i r r i g a t i o n . In moat cases, they are used to l i f t water from

wel ls . The Persian wheel l i f t s water from we l l s , the shadoof which l i f t s water from wells or

r i vers (canals) and the t readmi l l , which l i f t s water from r i v e r s , are mostly found in Asia but

could be introduced in t h i s country as w e l l .

The high-speed and high-output centr i fugal pumps which supply water to urban areas or large

scale i r r i g a t i o n farms are beyond the scope of t h i s paper. But the medium capacity centr i fugal

or piston pumps driven by fuel engines and used to aupply water to rural communities need special

mention. A number of these were insta l led in many v i l lages in t h i s country but unfortunately

most of them are not working. There are many factors which have contributed to t h i s problem.

Lack of expertise in the v i l lages to repair the engines and pumps, shortage of spare parts and

the shortage and ever-r iaing prices of fuels are jus t a few of the factors.

Hydraulic rams, which are not very numerous in t h i s country, require neither foss i l f u e l ,

animal nor human power to pump water from running streams to very high levels. Although the

technology for th i s device has been i n existence for the last two centuries, i t s use in Tanzania

has not been widespread. A few hydrants were ins ta l led and used in se t t le r coffee and s isa l

estates around Arusha and Moshi about for ty to f i f t y years ago, but most of them are not working

now due to neglect. In recent years, however, people have come to real ize the usefulness o f

hydram8, especial ly af ter engine operated pumps fa i led due to reasons mentioned above. During

th i s period there have been e f fo r ts to continue production and supply of hydrams in Tanzania.

Jandu Plumbers L td . of Arusha has been the only local manufacturer of hydrams.

HYDRAM PERFORMANCE

The performance of a hydram i8 determined by the working f a l l down which the dr iv ing water

t rave ls and also by the ver t i ca l height to which the pumped water must be raised. Thus, when

working f a l l and ver t i ca l height are know, the output can easi ly be determined from operating

charts or tab les. The increase of ver t ica l f a l l usually increases the amount of drive water and

thu8 increases the output of the hydram.

- 30 -

To calculate output of the hydram, some required information must be known. The v e r t i c a l

f a l l in meters, volume of drive water in l i t r e s per minute and the ve r t i ca l del ivery elevat ion in

meters must be measured accurately. A typical e f f ic iency of hydrams is around 60S. The output

can, there fore , be estimated according to the following simple formula:

D = V x F x 6_

E 10

where D z Output in l i t r e s per minute

V = Volume of water flowing through drive pipe in l i t r e s per minute

F = Ver t ica l (working) in meters

E = Ver t ica l e levat ion of del ivery in meters

After obtaining the D in l i t r e s per minute, hourly and da i ly outputs can be obtained by

mult iplying i t by 60 and 1,440 respect ive ly .

- 31 -

The table below shows the performance of a hydram at different working falls and delivery

heights

Working

Fall

(Meters)

1.0

1.5

2.0

2.5

3.0

3.5

4.0

5.0

6*0

7.0

8.0

9.0

10.0

12.0

14.0

16.0

18.0

20.0

Vertical height which water is raised above hydram (meters)

5

144

7.5

77

135

220

280

10

65

96.5

156

200

260

15

33

70

105

100

180

215

255

310

LITRES PUMPED 24 HOURS

20

29

54

79

125

130

150

173

236

282

PER LITRE/MIN OF DRIVE WATER

30

19.5

36

53

66

87

100

115

185

216

40

12.5

19

33

40.5

67

75

86

118

140

163

187

212

245

295

50

15

25

32.5

51

60

69

94

112

130

149

168

187

225

265

60

19.5

24

40

46

53

71.5

93.5

109

125

140

156

187

218

250

280

80

12.5

15.5

27

31.5

36

50

64.5

82

94

105

117

140

167

187

210

237

100

12

17.5

20

23

36

47.5

60

69

84

93

113

132

150

169

188

1

12

14

16

23

34.5

48

55

62

69

83

97

110

124

140

Source: John Blake Limited

- 32 -

SOME DESIGN CONSIDERATIONS

Over the years many researchers have been experimenting with new materials and new methods

of manufacture in an attempt to design a l iqhtweight hydraulic ram. Most of these l ightweight

designs have proven unsatisfactory due to the material not being strong enough to support the

high pressures which develop within the hydram. Although the hydrams have i n i t i a l l y performed

we l l , i t i s not known for how long they w i l l continue to funct ion. I t is doubtful whether they

w i l l be capable of running for f i f t y years or more, l i ke the t rad i t iona l ones made of heavy cast

s tee l .

Volunteers in Technical Assistance (VITA) and the Intermediate Technology Development Group

(ITDG), to mention jus t two organizations, have done research on simple hydrams which have been

f ie ld- tested with encouraging resu l ts . The VITA hydram i s constructed from available galvanized

i ron pipe f i t t i n g s and locally-made valves. The construction requires no special s k i l l and

minimum number of too ls . A d r i l l press and some hand tools are a l l that i s required. Welding,

brazing and soldering are not required. The cost o f the hydram i s very low compared to the cast

one but i t s du rab i l i t y i s yet to be determined.

The f i r s t consideration for hydram design i s du rab i l i t y . The hydram exploi ts the

non-compressibil ity of water. I f water flowing at a cer ta in speed i s abruptly stopped, a high

pressure (water hammer) w i l l develop. The hydram u t i l i z e s t h i s property by harnessing the water

hammer and any pump body with a tendency to expand under pressure or i s made of weak material

must not be used as i t w i l l break. Although rather expensive, i t i s necessary to use heavy

non-elastic mater ials. Heavy cast steel with parts of copper and brass have proved most i dea l .

Another very important consideration is the internal contour of the hydram body, both from

the point of view of f r i c t i o n s ! losses which w i l l prevent the maximum speed from being achieved

and ai r pockets which w i l l prevent attainment of maximum pressure. Loss of speed and pressure

w i l l seriously affect the ef f ic iency of the pump.

The success of the hydram w i l l be guaranteed i f r i g i d materials are used, i f i t i s cor rect ly

made and insta l led and requires very l i t t l e a t ten t ion . The workinq parts which need changing

about once a year are the rubber valve discs. Only simple maintenance i s required to ensure that

the waterways are clear and f ree-f lowing.

- 33 -

MANUFACTURE OF HYDRAMS

The manufacture of hydrams in Tanzania i s not as widespread as would have been expected,

taking, into consideration the acute problem of water l i f t i n g . There exists adequate

manufacturing, f a c i l i t i e s but the main constraint on widespread local manufacture of the pumps i s

that s t r i c t qual i ty control during manufacture i s essential i f the ram is to operate e f f i c i e n t l y

for a long period of t ime. Well made pumps have been known to run continously for more than

f i f t y years with only minimum maintenance but poorly engineered pumps break down easi ly and

quick ly .

During the era of cheap o i l of the 1950's and 1960's, interest in the use and, therefore,

the manufacture of the hydrams waned in Tanzania and elsewhere. However, due to the fact that

hydrams require no fuel to run them, they are now back in favour. Because of t h i s lapse in

interest for they hydrams, many people do not know much about them, but now that they have been

rediscovered, they should be popularized and made avai lable.

In Europe and America, a few firms are s t i l l manufacturing hydrams, though not as a main

product l i n e . John Blake L td . of England and Rife Hydraulic Engine Manufacturing Co. of New

Jersey, U.S.A. are well known and experienced hydram manufacturers. Unfortunately, hydrams from

these long-standing manufacturers are not being imported into Tanzania. The few imported hydrams

were ins ta l led before the cheap o i l era. One of the main reasons for the underut i l izat ion of

hydrams i s a lack of awareness of t h i s technology among potential users.

The sole manufacturer of hydrams in Tanzania i s Jandu Plumbers L td . of Arusha. A variety of

sizes are produced but the production rate i s very small. Only about ten hydrams are produced

per month but the demand for them i s increasing, both wi th in the country and in neighbouring

countr ies. Jandu Plumbers could produce more i f the hydrams were made the main product l i ne . As

mentioned ea r l i e r , there are a number of manufacturing firms in Tanzania with adequate f a c i l i t i e s

to produce hydrams. These firms could be persuaded to include hydrams as a product l ine and

would be w i l l i nq to do 30 i f the market could be guaranteed. Small scale industr ies which are

mushrooming a l l over the country could be u t i l i zed to manufacture the hydrams, especially at the

assembly stage. Complicated parts could be manufactured by medium or large scale industries

which have better production f a c i l i t i e s . Small scale industries could produce the simple parts

and perform simpler operations and the f ina l assembly.

- 34 -

THE HYDRAULIC RAH PUHP IN KENYA

Oyuko 0 . Mbectie

ABSTRACT

The present r u r a l water supply s t r u c t u r e i n Kenya i s o u t l i n e d , and re fe rence made to the

r o l e of hydrams. Community invo lvement , o r a a n i z a t i o n a l f i n a n c i n g , ope ra t i on and maintenance and

pub l i c hea l th aspects of r u r a l hydram development are surveyed.

INFORMATION

Reports from the M i n i s t r y of Water Development (MWD) s t a t e t h a t the access o f the r u r a l

popu la t ion to improved water supp l ies va r i es w ide ly from 13-15% as a n a t i o n a l average to 3-48 i n

some d i s t r i c t s . The Government, through the M i n i s t r y , has i n i t i a t e d four n a t i o n a l Rura l Water

Supply Programmes over the years i n v o l v i n g some 280 schemes, h a l f o f which are o p e r a t i o n a l , w i t h

the other under design or c o n s t r u c t i o n .

I t i s est imated tha t one -ha l f to t w o - t h i r d s o f the r u r a l popu la t ion w i t h access to an

improved water supply i s d i r e c t l y supp l ied through the MWD schemes. The r u r a l water supp l i es

under the MWD are admin is tered mainly through the f o l l o w i n g programmes:

Rural Water Supply Programmes (RWSI, RWSII, RWSIII and RWSIV) s t a r t e d i n e a r l y 1970

S e l f - h e l p Schemes Programmes

R e h a b i l i t a t i o n Programme

I n t e r n a t i o n a l agencies and b i l a t e r a l donors, fo r example, t he Government o f Sweden through

SIDA and the World Bank, have over the years ass is ted the RWS i n the coun t ry .

Hydraul ic ram pumps along w i t h o the r types o f pumps have been used i n many S e l f - h e l p Schemes

Programme f o l l o w i n g the 1976 I n t e r n a t i o n a l Women's Year - Harambee ya Wanawake Kwa A fya . In the

e a r l y 1950's and p r i o r to 19R0, Br i t i sh -made hydrams dominated the Kenyan marke t . Today i n 1984,

due to s t r i n g e n t c o n t r o l s on f o re i gn exchange, the major f i rms who had been impor t i ng these and

s i m i l a r foreign-made hydrams, no longer s tock them. The inexpensive In te rmed ia te Technology

- 35 -

Development Group (ITDG), U.K., and Volunteers i n Technical Assistance (VITA), USA, hydrams

produced at rura l and v i l l age polytechnics in the country are now more popular among rural

communities.

COMMUNITY INVOLVEMENT AND ORGANIZATIONAL FINANCING

The Kenya Government, through i t s Ministry of Water Development has been able to implement

various water schemes in the country. The Min is t ry , however, has indicated that the problem

experienced in water supply i s the d i f f i c u l t y in obtaining payment for the water supplied coupled

with the lack of community involvement. A water use study carr ied out by the Ministry has

revealed that only about 30-5055 of water d is t r ibuted and invoiced in the rura l areas in Kenya are

paid for by the users. The reason i3 that due to cul ture and t r a d i t i o n , water i s free and the

idea of paying for water i s altogether strange, i f not repugnant. This defeats many 3elf-help

e f f o r t s , such as the Rural Development Fund (RDF), by k i l l i n g any forthcoming cash contributions

and possible labour input. S imi lar ly , the use of communal water points have suffered setbacks

due to questions of revenue co l l ec t i on , respons ib i l i t y and ownership.

OPERATION AND MAINTENANCE

Different types of ownership generate d i f fe rent management s t ructures, due to the fact that

d i f fe ren t problems arise depending upon whether the structures are p r i va te ly , i n s t i t u t i o n a l l y or

pub l ica l ly owned. The most d i f f i c u l t problems arise from types of ownership resul t ing in

unfairness in d i s t r i b u t i o n , such as the exclusion, r e s t r i c t i o n and interference in i ns t i t u t i ona l

a c t i v i t i e s . Other problems result from the general fa i lu re of water users, par t icu lar ly in

communal government pro jects, to share respons ib i l i ty for hygiene and cleanliness at the source.

For example, sometimes communities f a i l to contr ibute the labour required to prevent the pumping

s i t e from lapsing into a state of d isrepai r . F ina l l y , for many government or donor projects i n

the rura l communities a common problem i s one of a lack of follow-up with a re l iab le maintenance

system. The ideal s i tuat ion would occur i f people at the communal or v i l lage level would be able

to buy, own, manage, maintain, repair , and overhaul or replace the pump, i f and when the need

ar ises. For every pump ins ta l l a t i on there i s also a need for local organization wi th in the

communities with an elected and highly motivated management committee to insure a re l i ab le

program of future care and maintenance.

- 36 -

PUBLIC HEALTH

I t i s a truism that a community cannot exist without water. However, access to that water

has direct and imp l i c i t costs to the community. These costs vary with each community in terms of

time and energy spent in co l lec t ing water, i l l - h e a l t h due to lack of suf f ic ient water, i l l - h e a l t h

due to contaminated water, and in some cases, actual cash paid for water.

At the outset, i t i s important to determine a community's health s i tuat ion which should

include:

1. the determination of the incidence of water-related diseases, such as skin diseases,

trachoma, diarrhoeas, cholera, b i l ha rz i a , and others;

2. the community'8 level of knowledge and awareness;

3. the community'8 practices and expectations; and

4 . the community's social and economic st ructure.

After determining the communities' health status, a sustained programme of water and health

education should be developed to create an awareness and appreciation of clean, safe water in

rural areas through community involvement and pa r t i c ipa t ion .

- 37 -

HYDRAULIC RAN PUMP TECHNOLOGY AND PRACTICE IN ZAMBIA i " * i

W.T. Weerakoon and V. Liyanage

ABSTRACT

A hydram ins ta l l a t i on in the Western Province of Zambia i s examined in d e t a i l . I t s h is tory

of usage, modifications and improvements are documented. Test resul ts and analysis for t h i s

hydram ins ta l l a t i on are given.

The rura l water supply s i tuat ion in Zambia i s surveyed with emphasis on community

par t ic ipa t ion programs. Research on locally-made hydrams at the University of Zambia i s

described and preliminary conclusions are drawn.

INTRODUCTION

Histor ical information reveals that hydraulic ram pumps have not been used in Zambia except

i n a few instances. This may be due to the fact that the f u l l potential of t h i s par t icu lar

technology has not been exploited. However, i t appears that windmills have been most popular

among farmers to l i f t water from boreholes. With the introduct ion of engine and

e lec t r i ca l l y -d r iven pumps, windmills too, got phased out of the system. The only known hydram is

insta l led at St . Mary's Mission in Kawambwa (Luapula Province). This pump was ins ta l led in 1961

and has a supply head of 9 metres and del ivery head of 70 metres. The diameter of the drive pipe

i s 6 inches (150mm) and the capacity i s 182m /day. The main storage tank i s situated at a

distance of 3.5km away. After nearly f i f t een years of use, t h i s pump has had to be repaired

several times. Main repairs were carried out on the del ivery pipe and bronze impulse valve

seat. Since 1976, t h i s pump has not been operating properly. I t was repaired once again by the

Technology Development and Advisory Unit (TDAU) and i t i s now in operation with an output of

144m3/day.

Due to the increased price in fuel and d i f f i c u l t y in obtaining foreign exchange, i t has

become necessary to look at the poss ib i l i t y of reintroducing hydraulic ram pumps in Zambia. At

present, Zambia has to re ly on engine- or e lec t r i ca l l y -d r i ven pumps. The maintenance of these

pumps are now becoming expensive and d i f f i c u l t . The hydram because of i t s low cost, ease of

operation, dependabil i ty, ef f ic iency and s impl ic i ty in construction offers a better choice to

Zambia than other pumps. However, these pumps w i l l be restr ic ted to specif ic areas where a

suf f ic ien t and steady water supply i s available with a minimum required water head.

- 38 -

Since hydrants have not been widely used, i t i s not possible to provide comprehensive

information about the i r operation. However, i t can be concluded that due to foreign exchange

d i f f i c u l t i e s and a lack of in f ras t ruc tura l f a c i l i t i e s avai lable, repairs and maintenance of

conventional pumping systems has become an extremely d i f f i c u l t task. I t i s in t h i s context that

hydrams can play an important ro le , both i n the community water supply and agr icu l tura l

development.

THE HYDRAULIC WATER RAM PUMP I N THE WESTERN PROVINCE

The hydram at the Bubenshi River was ins ta l led by the manufacturer in 1961, when St. Mary's

Mission was established in t h i s region. The water i s taken from the r iver at a spot of 9m above

the hydram. I t i s led through a pipe to an open surge tank, 36m from the ram. From there, the

water goes through the drive pipe to the ram (see Figure 1 ) . The breather pipe was not present.

The ram pumped the water through a 3.5km long 2-inch (50mm) del ivery pipe to the main storage

tanks, 70m above the ram. According to the manufacturer's data, the ram capacity was 100m /day.

From the s t a r t , the ram ins ta l l a t i on experienced a technical f a u l t : the dr ive pipe burst .

A team from the manufacturing company (Blake) v i s i ted the s i t e and suggested strengthening of the

drive pipe, especial ly at the elbow bend.

The community, using water from th i s i n s t a l l a t i o n , was expanding and af ter some time the ram

was considered to be too small. I t was replaced by a diesel pump and later by two e lec t r i c

pumps, a l l situated in a pumphouse near the i n l e t of the supply pipe of the surge tank. The

e lec t r ic pumps have a combined capacity of 290m /day.

However, the maintenance of the diesel pump became increasingly troublesome, and the power

supply to the e lec t r i c pumps was i r regu la r , especial ly during the rainy season. An automatic

on/of f switching mechanism for the e lec t r ic pumps fa i led to operate. This led to an e r ra t i c

water supply, sometimes interrupt ing the water supply to the users. To overcome these problems,

i t was decided to use the hydram ins ta l l a t i on again.

During the i n i t i a l use of the hydram, the bronze impulse valve seat had shattered. A new

cast - i ron valve seat was copied from the remainder of the o ld one and instal led in 1975.

Meanwhile, the delivery pipe of the ram was increased to 3-inches (75mm) and led from the hydram

to the pumphouse, where i t was connected to the pump's del ivery pipe. According to Blake's data,

the ram can pump up to 182m /day under these circumstances. These flows have not been obtained

at t h i s s i t e . When the TDAU engineers v is i ted the s i t e , the hydram was pumping, but only

occasionally did th i s flow reach the tanks.

- 39 -

MODIFICATIONS CARRIED OUT ON THE HYDRAM

The interference of shock waves in the drive pipe caused an ef fect ive hydraulic blockage i n

the pipe. I t may have been contr ibut ing to the bursting of the drive pipe as w e l l . To overcome

th i s inter ference, a breather pipe was welded on the drive pipe about 4m downstream of the elbow

(see Figure 1 ) .

The rubber of the faul ty non-return valve was cut to the appropriate s ize. The holes in the

impulse valve seat were cleaned. The diameter of the hole in the impulse valve rubber was

increased over a depth of 5mm to allow a greater valve opening. Provisions were made to have the

rubber move easi ly over the valve seat (see Figure 2 ) .

F ina l l y , the valve rubber was secured by a tapered rubber washer in the lowest pos i t ion.

The diameter enlargement in the rubber had to extend over 10mm in length in t h i s configuration

(see Figure 3 ) . Several other modifications have been t r i ed out with d i f ferent resu l ts . None of

these were f i n a l l y incorporated and are therefore not included in t h i s paragraph.

RESULTS OF THE MODIFICATIONS

After the i ns ta l l a t i on of the breather, i t was found i n i t i a l l y that the ram was s t i l l

beating i r regu la r l y and weakly. The interference of shock waves in the drive pipe could no

longer be observed. After cleaning the holes in the impulse valve seat and the introduct ion of

the cut-out in the valve rubber, the ram beat became strong and steady. Systematic tests of th is

modif icat ion - indicated as f loat ing valve rubber - were carried out. The complete test resul ts

are presented in Tables 1 and figures 4 and 5. I t was found that the hydram was pumping up to

48m /day with a high beating freguency.

An attempt to increase the hydram performance by increasing the stroke of the non-return

valve fa i led completely. The hydram was only pumping air and the output in the tanks was n i l .

Blocking one of the four a i r vents did not a l ter t h i s . Next, the impulse valve rubber was

secured in the lowest posi t ion by a tapered rubber washer. With t h i s modif ication systematic

tests were carr ied out as we l l . The complete test resul ts are presented in Table 2 and figures 4

and 5.

- 40 -

TABLE 1

Hydram performance, measured at main storage tanks, floating valve rubber

Valve sett ing

(revolut ions)

1

2 3

4

5

6

Pumped volume (m3/day)

10

39

41

45 48

48

Ram speed

(beats/min)

114

110

108

108

106

106

TABLE 2

Hydram performance, measure at main storage tanks, fixed valve rubber

Valve sett ing (revolut ions)

2

3

4

5 6

7

8

8 + 1 pump

8 + level

control

Pumped volume (m?/day)

51 91

108

115 123

119

132

290 123

Ram speed (beats/min)

108

80

66

60

58 56

56

— 56

- 41 -

The hydram performance increased dramatically while the beating frequency reduced. The

maximum pumping capacity was found to be 132nr/day. To reduce the chance of pumping air, the

water level in the surge tank of the ram was controlled by letting small amounts of air escape

through a tap. This reduced the ram performance by 88.

Using a flat rubber washer instead of a tapered one increased the maximum measured ram

performance by 8S to 144m'/day. After fifteen hours pumping, however, the outer part of this

washer was completely smashed. The surface of the valve seat was also damaged; small parts had

disappeared. It was also found that with the fixed valve rubber, the hydram could cooperate with

one electric pump. The pumping capacity was then 290m-yday which is just as much as both

electric pumps. A third pump further increased the pumped volume of water.

DISCUSSION ON THE TEST RESULTS

It can be seen clearly from figures 4 and 5 that the fixed valve rubber modification had the

highest pumping capacity and the lowest beating frequency. Reducing the maximum stroke of the

impulse valve rubber reduced the pumped volume and increased the beating frequency.

The largest measured volume of water being pumped was 75% of the manufacturer's prediction.

Unfortunately, only the diameter of the delivery pipe and the delivery height was stated, and it

is not clear whether the friction of the 3.5km delivery pipe length was included as well. Both

floating and fixed valve rubbers increased the effective taper of the impulse valve. However,

the required axial movement of the floating valve rubber was apparently much slower as compared

with the elastic bending of the fixed rubber and reduced the magnitude of the waterhammer shock

wave needed for pumping. Since it was observed that the beating frequency with the floating

rubber was higher and didn't vary very much with the valve setting, the conclusion may be

justified that the valve never opened completely. This would reduce the maximum waterflow

through the impulse valve and therefore reduce the waterhammer pressure. The damage of the

surface of the valve seat may have three causes:

Cavitation or surface fatigue

Corrosion of the valve 3eat during the six-year inactive period

Casting faults

- 42 -

I f the damage was caused by cavi tat ion or surface fa t igue, the damaged area w i l l increase,

eventually leading to fa i l u re of the valve seat. In t h i s case, one may use a harder material for

the valve seat, l i ke cast steel to delay or stop the phenomenon. I t may be possible, and even

l i k e l y that due to the waterflow and the impact of the valve ruber, corroded parts have been

cleaned and small b i t s of material near shrinkage cracks or graphite inclusions have been torn

o f f . In th i s case, the damaged area w i l l not increase.

COMMUNITY PARTICIPATION

Community involvement and par t ic ipat ion in water projects has been one of the b u i l t - i n

features in Zambia. According to the Third National Development Plan (TNDP), i t i s c lear ly

stated that the Ministry of Health and a l l those working in the health f i e l d w i l l redouble the i r

e f fo r t s in educating and mobil izing the people to take greater responsib i l i ty in promotion and

preservation of health and prevention of diseases. Since the Government alone cannot provide

adequate water, refuse disposal and environmental health f a c i l i t i e s for a l l , comminities w i l l

therefore be encouraged to undertake these projects on a communal basis, with the technical

advice available from the Ministry of Health, Water A f fa i rs and other agencies. An example of

such a community ac t i v i t y i s the Public Stand Water Supply i n Mwachisompola Health Demonstration

Zone.

Organization of public par t ic ipa t ion i s usually encouraged through exist ing networks and

government agencies. Usually, project managers seconded from the i r respective duties for a

specif ic period in these projects are the key f igures responsible for organizing public

par t i c ipa t ion . Financing comes from ei ther the Government or outside agencies. For example,

funds for the above project came from the Internat ional Reference Centre for Community Water

Supply (IRCCWS) in the Netherlands.

In almost a l l pro jects, due to lack of technical ly qua l i f i ed manpower, breakdowns occur

which are not attended to immediately. Lack of spares and transport and preventive maintenance

programmes can be said to be the other features that aggravate t h i s s i tua t ion . Training of

manpower and educating the communities can go a long way to cope with t h i s s i t ua t i on .

RURAL WATER SUPPLY SITUATION IN ZAMBIA

During the Second National Development Plan (1972-1976), about 1,531 wel ls , 342 well points,

652 boreholes and 100 piped water supplies were completed under the Vil lage Cooperative and Water

Supplies Programme. Approximately 250,000 people benefited from these f a c i l i t i e s , bringing the

- 43 -

t o t a l of rura l population with hygienic water to 2.1 m i l l i o n . During the TNOP (1979-1983), some

progress was made, but due to increased fuel prices and er rat ic behaviour of the world economy,

i t was not possible to maintain the same speed of progress.

S t i l l , large numbers of people have no access to clean water supply. Due to an absence of

adequate re l iab le water supply, many chi ldren under the age of six years d ie . S ta t i s t i ca l

reports indicate that more than 70S of the diseases are connected with unclean water. An attempt

has been made by the Government and local author i t ies to make available safe water to a l l rural

v i l l ages . Although c i t i e s and urban areas usually have sat isfactory water storage and

d is t r i bu t ing f a c i l i t i e s , s t i l l much more work i s needed to make clean water available to the

rura l population.

RESEARCH AND DEVELOPMENT ACTIVITIES

The f i r s t research and development a c t i v i t i e s related to hydrams started in 1975 by the

Magoye Regional Research Station (Department of Agr icul ture) i n Magoye. The second pump was

manufactured by Jere (TDAU). Both these pumps had not been previously tested properly, so that

i t was f e l t necessary to carry out tests to determine the operational v i a b i l i t y of these pumps.

Work reported here i s a resul t of the extensive work carr ied out by Mwafulilwa of School of

Engineering. This project was j o i n t l y sponsored by the School of Engineering and Technology

Development and Advisory unit (DTAU).

The purpose of the Lusaka project was to determine the performance of the TDAU and Magoye

manufactured hydrams in order to examine the ef fect of varying the supply head, supply ra te ,

dr ive pipe, impulse valve stroke and tension, the hydram beat frequencies, delivery height and

the del ivery rate on the ef f ic iency and performance of the hydram.

The following conclusions were reached from the tests carried out on the two pumps:

1 . An increase in number of cycles per minute decreases the e f f ic iency. This can be seen for

the curves 5 and 6 (see Figure 6 ) .

2. The del ivery rate increases with the increase in ef f ic iency up to a certain point only (see

Figure 7 ) .

- 44 -

3. An increase in del ivery head tends to decrease the overa l l ef f ic iency of the pump. The

maximum del ivery head seems to depend more on the supply head than the impulse valve

sett ings (see Figure 8 ) .

F ina l l y , the Lusaka project indicated that these pumps can be easily used for active water

pumping, since they perform wel l under the environment in which they were tes ted. However, i t i s

important to f i e ld - tes t them before any decision can be made to manufacture them l oca l l y . I t i s

also f e l t that some other designs should be introduced for f i e ld - tes t i ng to compare the

ef f ic iency of each design and select the ones best suited to the local condit ions.

CONCLUSION

The Third National Development Plan c lear ly indicates the necessity to generate more and

f u l l e r employment as a major objective of development, and to that end, to adopt technlogy which

i s labour- intensive, paying due regard to the resources available and the social needs of the

Zambian economy. Further d i ve rs i f i ca t i on of the economy from a copper base to agr icul ture has

been emph°sized by the Party and i t s Government in the i r e f fo r ts to reduce the economy's

dependence on copper. Besides these object ives, the basic need to supply clean water for

drinking i s also an important factor in any rura l development in Zambia. There i s an urgent need

to have an active research programme in hydraulic ram technology i n Zambia and to undertake

research and demonstrate the capabi l i ty of t h i s inexpensive technology which needs very l i t t l e

s k i l l s to maintain. I t i s also important to t r a i n the local artisans to manufacture and maintain

these pumps at the v i l l age l e v e l .

- 45 -

TABLE 3: NOTATION FOR CURVES ON FIGURES 6, 7 AND 8

a) SUPPLY HEAD = 3.205m

Curve Number Valve Stroke Bolt Tension

(mm) (no. of clock-wise turns)

1 10 0

2 20 0

3 30 0

b) SUPPLY HEAD = 4.22m

Curve Number Valve Stroke Bolt Tension

4 10 0

5 10 1

6 10 2

7 20 0

8 30 0

REFERENCES

1. Report on Trouble Shooting Visit to Water-ram in Kawambwa, Luapula Province. Colijn, A;

Hommer8on, G.; Shouten, C.P.; and Vlugman, A.A. 1982.

2. The Hydraulic Analysis of Water Rams. Mwafulilwa. 1983

3. Public Standpost Water Supplies, Volume 13 and 14. IRCCWS Publication. 1979.

4. Third National Development Plan, Zambia. 1979.

5. Public Stand Water Supplies (PSWS) Project Lusaka. 1983.

- 46

5 a z

hi >

a: x V) 111 o z> CD

W X

< _J _ l <

V)

<

a >-x UJ X

ID

o

U.

- 47 -

ce UJ CD CO z> or UJ

3

CD

< O

UJ

§ UJ CO _l 3 Q.

CM

U_

- 48 -

00 CD 3 ac UJ

§ Q UJ X

UJ

5 UJ

-i

QL

2

ro

S2 u.

Q

UJ

O I z 2

o

UJ

_) o >

IMPULSE VALVE SETTING No. OF REVOLUTIONS VALVE SPINDLE FROM FULLY CLOSED POSITIOr

FIG. 4 : HYDRAM PERFORMANCE CURVES

- 50 -

z

UJ

m

o LU UJ 0 .

(/) ID

< > Hi

_J

IMPULSE VALVE SETTING

( No. OF REVOLUTIONS OF THE VALVE SPINOLE FROM FULLY CLOSEO POSITION )

FIG. 5 : HYDRAM FREQUENCY AS A FUNCTION OF IMPULSE VALVE SETTING

- 51 -

150

HYDRAM CYCLE /MIN.

FIG. 6 : EFFICIENCY VS. BEAT FREQUENCY

>-o z LJ

o LL

u.

DELIVERY RATE (^/MIN.)

FIG. 7 : EFFICIENCY VS. DELIVERY RATE

DELIVERY HEAD (M)

FIG. 8 : EFFICIENCY VS. DELIVERY HEAD

- 54 -

PRACTICAL ASPECTS OF HYDRAM OPERATION

E . J . S c h i l l e r

ABSTRACT

Selection of the correct hydrant for a given physical s i t e i s considered. The measurement o f

f i e l d parameters and s i te construction i s ou t l ined. Some key operation and maintenance factors

are noted.

INTRODUCTION

In the following paper some pract ical aspects of hydram ins ta l l a t i on and operation w i l l be

discussed. The f i r s t question to be addressed i s the select ion of the hydram, in terms of type

and size for a given s i t e . Having correct ly ins ta l led the hydram, questions of dai ly operation

and maintenance need to be considered.

SELECTING A HYDRAM FDR A GIVEN SITE

I t was previously shown that two character ist ic curves embody most of the operating

character is t ics for a given hydram. The correct use of these curves can aid in choosing the best

hydram for a given s i t e . HEADER

TANK

STRAINER DELIVERY

VALVE

AIR-VALVE

FIGURE 1 : A TYPICAL ARRANGEMENT I N A HYDRAM INSTALLATION

- 55 -

SITE PARAMETERS

A given s i te will have the following parameters which will usually need to be measured in

the field.

i ) Stream Flow. Stream flows can be measured by various methods including the volumetric

method for very small flows.

SffttMfr

LnAu»«rt

O HtAvotLuofa-* i r iN .1 n . « J .

and the temporary V-notch weir f o r larger f lows, Watt (1978)

Te>*PDfl.At.V t A M tOlTH \AM0TOi.

WITH -J MQTCH t

UOTCH WJtlt

ft - C»\.

k% MEAS.o(L>»Jfa L»MUi£ft. F l_ou3 i

ME.AfcU&£HENT «3F lOATER. fcEPTH H OHJE

HE-IE<L oi>feT(tcftM FRaM v*-oAOTtrt wci<t. Watt ( 1 9 7 8 )

Tor even larger flows, velocity measuring meters (ei ther the pygmy type or the large Price

and Ott current meters) can be used. Sufficient readings of the stream flow should be taken in a

yearly cycle to determine the minimum guaranteed flow available (_min).

- 56 -

The drop in the flowing stream from the source to the s i te of the hydram is an important

parameter. The stream may have a natural drop or a drop can be created by means of a

small dam. The amount of th is drop can usually be determined with a simple surveying

level or even with a carpenter's level attached to a s t i ck .

l A j f x a . U ^ l *»t*m

ak sou ret. <L«.«1 kaKa?*

V

l a m e posikU/t

Hi

4oumk'tl\ a A l tak*. a. rfla-dwvq

J-H^fcUMSiTi.

tf&tt (1978)

i i i ) The distance from the hydram s i te to the storage point must be measured both i n terms of

the l i f t required (H^, Figure 1) and i n terms of the length of the delivery pipe

required.

iv) An estimate o f the water demand i s required. I f t h i s i s to be used for domestic

consumption in a rura l se t t i ng , th i s can be approximated by:

Water Demand = Population x Per Capita Consumption (1)

A typical per capi ta l consumption i3 30-40 L/p/day. I f animals are present, the i r water

consumption should be included also.

MATCHING PUMP CHARACTERISTICS TO THE SITE AND DEMAND CHARACTERISTICS

Given the water demand from equation (1) and the fact that hydrams operate twenty-four hours

per day, the required flow w i l l be:

Q = Water Demand ( l i t r e s ) (2) 24 x 60 (min)

- 57 -

We next refer to curve9 of pimp ef f ic iency for the same supply head, H, as was measured at

the s i t e . We should select a pump that works near i t s maximum ef f ic iency at the flow given in

equation (2 ) . Curves derived by a computer model w i l l greatly f a c i l i t a t e the pump selection

process.

When a pump has been selected, the head ra t io - f l ow ra t io curves can be consulted. The pump

w i l l need to supply enough pressure head to l i f t the water to the storage tank and to overcome

a l l f r i c t i o n losses in the del ivery pipe. In general, t h i s w i l l be equal t o :

Delivery head = Hd + (fL_+ Ek) _V^ D 2g

where Hj = height to which water i s l i f t e d

f = pipe f r i c t i o n factor

L = del ivery pipe length

D = del ivery pipe diameter

V = average veloci ty in delivery pipe

E^ = sum of various minor losses i n del ivery pipe

g = acceleration due to gravi ty

Once the required del ivery head i s determined, the head ra t i o can be determined. From the

head-ratio versus f low-rat io curve, the flow ra t ios (Q/Qw) can be determined. The sum of the

del ivery flow and waste flow must be le3s than the minimum guaranteed stream f low, i . e .

Q + Qw <Qmin (3)

Highly e f f i c i en t pumps reduce Qw. I f the stream flow i s abundant, the hydram choice may

emphasize durab i l i t y more than e f f ic iency.

HYDRAM SITE CONSTRUCTION

In most cases a small dam w i l l need to be b u i l t . The drive pipe must enter the dam high

enough from the bottom to avoid sett led debris that w i l l accumulate at the bottom of the

headpond. The dr ive pipe should be f i t t e d with a screen mesh to eliminate debris that would

enter the drive pipe. This would tend to increase the wear of the waste valve and the del ivery

valve.

- 58 -

The drive pipe should be well braced, for i t w i l l have a high pressure wave t rave l l ing up

along i t . Care should be taken to ensure that pipes w i l l not resonate with the imposed beat

frequency of the hydram. F ina l l y , the hydraro i t s e l f should be well mounted on a concrete pad,

with provision made for proper drainage of the waste water away from the hydram and back to the

stream source. This feature i s essent ia l , and any s i te that cannot allow proper drainage from

the hydram s i te should not be chosen.

F u f c t f t TAaJK.

ZaofULE.

70 ST»ftA<£C

WAttR.

f l R v / B(J 0.CXKV i N S f A l A T i o M . Watt (1978)

OPERATION WO MAINTENANCE

The hydram operates continuously with only two points of wear at the waste and del ivery

valves. Eventually, these valves w i l l wear out and need replacement. Spare rubber disks should

be kept on hand to repair these two valves when th i s occurs.

The drive pipe strainer should be checked per iodical ly and cleaned as needed.

The ai r valve should be kept clear and clean. I f a i r ceases to enter the hydram, very noisy

and i r regular operation w i l l r esu l t .

Most hydrams can be tuned by varying the stroke of the waste valve. When hydrams are tuned

they should be locked and not a l tered.

The above represent the major areas of maintenance. As long as the water supply is assured

and the pump i s kept free of debr is, long periods of t rouble- f ree operation can be obtained with

hydrams.

REFERENCES

Watt, S.F. (1978). A Manual on the Hydraulic Ram for Pumping Water,

Intermediate Technology Publications L t d . , London.

- 59 -

THE MANUFACTURE OF HYDRAMS

S.S. Jandu

ABSTRACT

Unreal ist ic approaches to local hydrant design and manufacture are examined. Some aspects o f

the manufacture of hydrams in Tanzania are considered.

INTRODUCTION

Jandu Plumbers Ltd. f i r s t began ins ta l l i ng hydraulic rams in East Afr ica f i f t y years ago at

which time the technology was already two hundred years o l d . The type of hydrams that Jandu has

ins ta l led had previously been in manufacture for over seventy years. Therefore, our i n i t i a l

react ion on receiving an inv i ta t i on to a seminar on the design and use of hydraulic rams was one

of surprise that i t should be necessary to do research into such a long-established technology.

We have seen hydraulic rams became beloved of the armchair Intermediate Technology ( I . T . )

and Appropriate Technology (A.T.) engineers for romantic rather than rat ional reasons. Indeed,

i t i s party for s imi lar reasons that we manufacture them ourselves rather than some more

pro f i tab le l i n e . However, as engineers, we now see that the problems of making t h i s sort of

technology available to the rura l population as a whole, are more social or even p o l i t i c a l than

techn ica l . We shal l be happy to leave th i s aspect to the experts but would l i ke to comment on

one example of the naive appl icat ion of the I .T. a t t i t ude . You w i l l a l l have seen the neat

hydram made from standard pipe f i t t i n g s and adopted by VITA. Now - t h i s i s very convenient for

the volunteer with the VITA handbook working in a remote area and with access to those f i t t i n g s ,

but do we foresee hundreds of v i l lagers descending on the i r nearest town to purchase f i t t i n g s and

then making and i ns ta l l i ng the ram in the vi l lage? We contend that i t i s much more l i ke l y that

such technology w i l l spread i f appropriate equipment i s readi ly available at the local market

town at reasonable pr ices. Tanzania i s , we bel ieve, not untypical of many developing economies

in i t s lack of spare parts and equipment. I f you were to set out to bu i ld the VITA ram here, you

would spend considerable time searching for the parts and should you be fortunate enough to f ind

them, then the open market value of the components would be quite high since they w i l l have been

imported into the country, and consequently be a foreign exchange cost to the country. I f you

add th i s to the time and expense of searching and assembling, then the cost i s considerable.

Surely then, i t is better to make available a commercially-built ram, or better s t i l l , to

encourage the local manufacture of a hydram.

- 60 -

We hear a great deal about the "transfer of technology". In our experience th is i s greatly

aided by having a foundry since th is has enabled us to find equipment that has served i t s purpose

and been well proven over the years and then, quite frankly, we copy the design.

We have been tempted to search for the most "efficient" hydram but now realize that i t i s

more important that the machine selected should be cost-effective in terms of f i r s t cost and

maintenance and that it should tend to keep working even when the conditions are not optimal. We

selected our pattern of hydram because i t i s simple in havinq no metal moving parts , no bearings

and no springs.

Our foundry has been buil t up over the last six years around the manufacture of the hydram

but has diversified into many other items in our l ine of water supply and plumbing equipment.

Our hydrama are made from locally-available scrap which i s selected into different grades for

different tasks and even the rubber valves are made locally by our supplier in Tanzania. Not

only the hydrama, but also the foundry i s made from local materials with the exception only of

some electric motors and fire cement. We would not expect a foundry to be supported by the

manufacture of hydrams alone and i t i s a further advantage of foundry work that once the cost of

patterns has been covered, i t i s not expensive to change from the manufacture of one item to

another to meet current demand.

One of the greatest aids to our type of small scale manufacturing industry would be the

abi l i ty to buy secondhand machine tools from Europe where machinery that would be invaluable to

us are frequently broken up for scrap. We have been lucky that through the good offices of the

Ministry of Industry, we have been able to do th is on one occasion and the machinery has been in

full production ever since. The potential for industrial development by such means i s huge, but

the restr ict ions on importation of secondhand machinery makes i t extremely d i f f icu l t .

Our customers have included: aid agencies working in rural development, mission hospitals ,

schools, agricultural research s ta t ions , and many farms and plantations. If financing were

readily available, villages would also buy d i rec t . Incidentally, we know there i s a

well-developed demand for the hyrams - from the number of thefts that are reported to us.

I invite you all to visi t our workshop and also see some of the hydrams that we have

installed in the Arusha area. Fran t h i s , you will have a bet ter idea than I am able to convey in

a speech, of the performance of the hydram and the problems we face in manufacture.

- 61 -

Jandu hydraas and a VITA hydran on display at Jandti Pluabera Ltd . , Arusha, Tanzania

The foundry at Jandu Pluabers Ltd, Arusha, Tanzania

- 62 -

COMMUNITY PARTICIPATION IN THE DEVELOPMENT AND MAINTENANCE

OF HYORAMS IN RURAL MATER SCIENCES

L.G. Mairi>e

ABSTRACT

A h is to r i ca l review of the role of community par t ic ipat ion in rura l water supply in Tanzania

i s qiven. Possible areas of local par t ic ipa t ion in a hydram development program are qiven.

INTRODUCTION

Community par t ic ipat ion in the development and maintenance of hydrams in water schemes has

to be seen as an inteqral part of the benef ic iar ies ' involvement in the to ta l development of

public services qiven to the rural populace, such as health centres, schools, roads, water

schemes, etc . Durinq the struqqle for p o l i t i c a l independence, and as a resu l t , in the early

years of independence, mass mobil ization was quite h iqh. As a resu l t , in the early years of

independence, people's par t ic ipat ion in what was then popularly known as sel f -help development

proqrams was remarkedly hiqh. The success of the famous 'MTU NI AFYA* (a person i s h is health)

campaign in the s ix t ies and the number of schools, dispensaries, and health centres bu i l t during

that time on a sel f -help basis c lear ly demonstrated the s p i r i t people had towards development

proqrams. In a nu tshe l l , people had accepted that development was their own responsib i l i ty and

that there would be no outside group who would help them in the transformation of the i r l i ves .

LOSS OF MOTIVATION

However, as years went by, that s p i r i t progressively faded away. Although there are many

factors which led to t h i s change of a t t i t ude , the fol lowing are a few of the main ones:

1 . Government involvement in the implementation of development schemes assumed a

predominant r o l e . The introduct ion of big development programs necessitated

i ns t i t u t i ona l management, and involvement of benef ic ia i r ies was ignored under the

pretext of achieving the objectives within a predetermined economic timeframe. Planners

fe l t that involvement was a parameter that they could not cont ro l .

- 63 -

2. The removal of local government author i t ies i n the early seventies meant development

programs would be more cent ra l ly planned and executed.

3. Some of the p o l i t i c a l decisions were misunderstood by the general public to mean the

government was duty-bound to provide the basic public services f ree.

4. The second ha l f of the s i x t i es and f i r s t ha l f of the seventies were very ' rosy ' times and

the government seemed f inanc ia l l y able to assume the role of providing for the basic needs

to i t s rura l populace.

5. Some government decisions disturbed the order in society to the extent that people could not

rea l l y i den t i f y the i r role in the development of the i r country.

6 . Some indiv iduals misused the exist ing potent ial of community par t ic ipa t ion for the i r own

benef i ts . Incidences are on record where people were persuaded to put e f for t into projects

which la te r had to be abandoned.

7. The present hard economic times characterized by shortages of many of the essential *

commodities has encouraged ind iv idua l i s t i c development.

8. Public par t ic ipa t ion was done on a voluntary basis. There was no leg is la t ion to enforce i t

and ensure i t s cont inui ty as a necessary input i n the development process.

9. There was no assessment made to evaluate the social and economic impact of comminity

development on development programs.

RESTORATION EFFORTS

In the course of t ime, the government real ized i t s l im i ta t ions in terms of resources and

implementation capacity. More importantly, the government real ized that development cannot be

'p lan ted ' . Benef ic iar ies ' involvement i s a ncessary input i f development programs are to be real

and meaningful. Therefore, the government i s now taking posi t ive steps to restore the apparently

lost glamour of local par t i c ipa t ion . As a f i r s t step, the government encouraged formation of

v i l l age governments which w i l l manage funds and provide public services. The process of v i l lage

leg is la t ion has been regrettably slow. The establishment of local government in 1983 is al30

seen as a posi t ive contr ibut ion towards react ivat ion of the sel f -help s p i r i t , although i t also

has some undesirable features l i t e personal tax.

- 64 -

As evidence of a new trend, a department of community participation has been established in

the prime minister's officer.

COMMUNITY PARTICIPATION POTENTIAL IN HYDRAH SCHEMES

Regarding the development and maintenance of hydrams used in rural water schemes, the

following tables indicate areas of possible beneficiaries' involvement.

TABLE 1: CONSTRUCTION

Activity

Site iden t i f i ca t ion Community mobil izat ion Survey Design Supervision of construction work Materials ( local ) Materials (foreign) Ski l led labour Unskilled labour Ins ta l la t ion Construction

Cmaunity Involveaent

+ +

X

X

X

+ X

X

+ • +

TABLE 2: OPERATION AND MAINTENANCE

Activity

Protect ion Attendance Running expenses Repairs Reporting Ownership

CoMftmity Involvement

+

+

X

+

+ +

NOTE: -t- - implies participation possible

x - participation is not possible

* - limited participation

Table 2 clearly demonstrates that there is a large scope of community involvement,

particularly in the operation and maintenance of hydrams.

- 65 -

CONCLUSIONS AM) RECOHMEJCATIONS

The need for community participation in development programs cannot be overemphasized. At

present, it is difficult to organize community participation. Therefore, there is a need to

conduct a study to ascertain the level of community participation that would be possible in the

development and maintenance of hydrams. The main objectives of the study should be the

following:

identification of options which will reactivate the spirit of community participation,

particularly in the development and maintenance of hydrams;

determination of cultural influences on the acceptability of hydrams;

assessment of attitudes of people towards water supply services;

assessment of local skills and their influence on the development and maintenance of

hydrams;

assessment of the level of need of service; and

determination of the influence of economic differences in the development and

maintenance of hydrams.

- 66 -

SOCIO-ECONOMIC CONSIDERATIONS IN RURAL MATER SUPPLY DEVELOPMENT

W. Baynit

ABSTRACT

Some cu l tura l constraints to hydram usage are noted. The d i f f i c u l t y with f oss i l - f ue l

pumping is enumerated and potent ial areas for hydram development in Tanzania are l i s t e d . Some

aspects of a hydram feas i b i l i t y study are given.

INTRODUCTION

Constraints to the application of any technology should not necessarily be confined to

technical aspects. Social and even p o l i t i c a l aspects may be crucial in constraining the demand

for a technology. This i s true for hydrants as well as any other technology.

SOCIAL CONSTRAINTS IN HYDRAM APPLICATION

When discussing the social constraints i n the appl icat ion of hydrams in Tanzania, a major

issue may be the potent ial users' lack of awareness and exposure to hydram technology in areas

where th is technology could be used. Other social and economic barr iers could include:

excessively high capi ta l costs, users' cu l tura l barr iers and sens i t i v i t i es , social structure of

the users' community-like settlement patterns, ownership pat tern , government po l ic ies , and

economic aspects such as i n f l a t i o n .

One of the main cu l tura l barr iers and sens i t i v i t i es of the rura l communities in Tanzania as

well as in most other African countr ies, i s supers t i t ion . The unique sound that hydrams make

while working could t r igger some speculation among the v i l l a g e r s . Some hydrams are ins ta l led in

strange-looking areas and l e f t unattended. There are thus no v is ib le paths leading to them and

yet the sound reaches quite a distance. This may make the v i l lagers suspicious and refuse to

accept the hydram as a useful t o o l . I t i s a commonly-held be l i e f that the natural water sources

l i ke springs are holy places and should not be tampered w i t h . Experience has shown tha t , i n some

cases, v i l lagers w i l l not only abandon the area in which the pump is insta l led but also the r i ve r

from which the hydram draws i t s water. Vi l lagers would rather look for an al ternat ive water

source which may be miles away than draw the i r water from a tarapered-with or "bewitched" r i ver or

spring. This problem w i l l be resolved through exposure to various working hydrams and education.

- 6 7 -

POTENTIAL FOR WIDESPREAD U5E OF HYDRAMS

Following the campaign to set t le peasants in Ujamaa (commLnal) vi l lages , a number of water

pumps were installed to supply water to these v i l lages . Most of the pumps were driven by

fossel-fuel engines and a few by windmills. The pumps were installed at a time when whe world

was about to bid farewell to the cheap fuel era. The villagers did not enjoy piped water for

long before the oi l c r i s i s struck. For some time more pumps continued to be installed as the

world expected the c r i s i s to be temporary but only recently has i t been realized that the cheap

o i l era i s gone forever.

With the ever rising prices of fossil-fuel and spares, the engines one by one ground to a

s top. Villagers who could afford the fuel and spares lacked the expertise to repair and maintain

the engines. The last blow came when fuel was in short supply and rationing was introduced. It

became very diff icul t for vil lagers to obtain the fuel although some had the money to buy i t .

The pumps were abandoned with unserviceable engines and the vil lagers had to revert to trekking

miles in search of water. The situation i s s t i l l the same today and there i s no indication of

ever reviving the engines again. In fact, some of the engines have been brought back to towns

where they are driving other machines, including grain mi l l s .

Windmills have been used to pump water in Tanzania but the in i t i a l costs of purchasing and

instal l ing them are out of reach of most vi l lages . The few seen here and there in some parts of

the country were bought by the government and instal led free-of-charge to the vi l lages. Even a

government cannot afford to supply a windmill free-of-charge to every village in the country.

Even with the few windmills supplied by the government, most of them are either not working or

the pumps are not working due to lack of regular maintenance.

The hydrant, therefore, i s the ideal alternative to the pumps mentioned above. The fact that

i t consumes no fossi l-fuel , needs minimum maintenance and can be reasonably priced, weighs

heavily in i t s favor. As mentioned ea r l i e r , the technology is quite simple and all the hydrams

which may be required can be manufactured locally. This will serve two purposes. Firs t ly ,

foreign currency can be saved, and secondly, the end users will have somewhere to turn in case of

problems.

There are many areas in Tanzania where hydrams could be installed both for domestic and

irr igat ion purposes. The Northern Highlands with fast-flowing rivers are quite ideal. It i s in

th i s area that some of the oldest hydrams were i s ta l led many years ago; some of them can s t i l l be

found in working condition. The Southern Highlands have numerous rivers running in deep ravines

formed by low h i l l s . Dwelling houses are built on the h i l l s making i t difficult to fetch water

up the h i l l s . Some hydrams can be found in th is area also.

- 6a -

The Usambara Mountains are another potential area for installing hydrams. The area has

plenty of rivers with many waterfalls but n»3t of the rivers run deep between steep, low hills

thus creating a problem of fetching water uphill. In the Dluguru Mountains, people live on the

slopes and a lot of rivers run down the slopes to the sea many miles away. As in the Usambara,

here also hydrams could be useful to lift water to the dwellings. The people living in these

areas are good cultivators of vegetables but they have difficulty in bringing water to the high

ground where they live and farm.

CONCLUSION AND RECOMHENATION

In Tanzania the experience of the failure of the engine-powered pumps should give all those

concerned a new outlook in rural water supply. The fact that a hydram uses no fossil fuel and

has the ability to work continuously for up to fifty years with minimum maintenance, confirms the

appropriateness of the pump. The experience of owners of hydrams installed around Arusha after

the cheap oil era proves further that hydrams have a future in this country.

It is true that the initial cost of the pumps and installation is rather high and beyond the

reach of most individuals. For domestic purposes, one hydram can supply water to a sizeable

community provided the storage tank is big enough. The cost, therefore, will be spread amonq all

potential users.

To promote the widespread use of hydrams in Tanzania, a feasibility study, especially of

water sources available and socio-economic aspects, must be made. The recommendations mentioned

below may prove useful in this respect.

1. A study on the use of hydrams should be carried out to find out the actual potential for

these devices. This will include water sources and the geograhical and socio-economic

aspects.

2. Efforts should be made to enhance the manufacture of hydrams within the country. More

entrepreneurs should be encouraged to use their facilities for this purpose. The small

scale industries which have been established in various parts of the country could be most

useful for this purpose.

3. Institutions such as CAMARTEC should be charged with the responsibility of selecting and

evaluating a few proven designs which can be manufactured locally.

- 69 -

The technology must be disseminated in the rural areas by launching a nation-wide campaign.

A few demonstration pumps could be installed in selected areas and villagers should be

encouraged to meet all expenses.

Owners should be trained to adjust the hydrams and to change worn-out working parts. This

also could be done by CAMARTEC or the manufacturers. Other maintenance aspects of the

hydram should also be taught to the owners.

Villages now are bigger and more populous than before the Ujamaa villages. This calls for

larger size hydrams, as these will be cheaper than a number of smaller ones.

- 70 -

FIELD TRIP PHOTOS

*' •- "jV

Twin-act ing hydra* in the Arusha area

Jandu Hydras, operating in the Arusha area

- 71 -

THE THEORY AND DESIGN OF THE AUTOMATIC HYDRALIC RAM PUMP

P.O. Kahangire

ABSTRACT

The automatic hydraulic ram pump and i t s generalized action are b r i e f l y described. The

basic methods commonly used to study the pr incip les of hydraulic ram operation are summarized. A

simple approximate analysis of the operation of the hydraulic ram pump and the resul tant

operating character is t ics are derived and presented. The theoret ical hydram model resul ts are

then compared with experimental resul ts for two hydrams.

The influence on hydram performance by ( i ) design features of the hydram i t s e l f , and ( i i )

such external parameters as the supply head, dr ive pipe length and veloci ty of water i n the drive

pipe are discussed. F ina l l y , topics for further research are examined.

INTRODUCTION

The Automatic Hydraulic Ram

A hydraulic ram pump (hydram) i s a unique device that uses the energy from a stream of water

f a l l i n g from a low head as the dr iv ing power to pump a port ion of the water to a head much higher

than the supply head. With a continuous flow of water, the hydram w i l l operate automatically and

continuously with no other external energy. Hydrams are suitable for small scale water supply

schemes, farmhou8es and isolated settlements (Schi l ler 1982).

The hydram i s s t ruc tu ra l l y simple consisting of two moving parts: the waste valve and the

de l ivery (check) valve. There i s also an a i r chamber and i n most hydrams, an a i r ( sn i f t e r )

valve. The operation of the hydram i s in termi t tent due to the cycl ic opening and closing of the

waste and the del ivery valves. The closure of the waste valve creates a high pressure r ise in

the dr ive pipe and hydram. The a i r chamber i s necessary to prevent these high pressures in the

del ivery pipe and transform the intermit tent pumped flow into a continuous stream of flow. The

a i r value allows a i r into the hydram to replace that absorbed by the water due to the high

pressures and mixing in the a i r chamber.

- 72 -

Hydran U t i l i za t i on

Hydrams can operate trouble-free for a long time and need no foss i l fuels or other external

source of energy other than the fa l l i ng stream of water. They are mechanically simple and

operate with re la t i ve ly high ef f ic iency and require only l imi ted simple maintenance. In spite of

a l l these advantages, the hydrams have not been u t i l i zed as much as they should. The hydram has

not been widely used part ly because the detai led mechanics of i t s operation are not well

understood. As a resu l t , s ign i f icant design improvements and variat ions have been d i f f i c u l t to

make and the commercial hydram remained almost the same for 190 years. The operating l im i ta t ions

of hydrams are al3o not well known. As a resu l t , the commercial hydran market remained small and

reserved for small scale appl icat ions.

RESEARCH INTO THE PRINCIPLES OF HYDRAM OPERATION

There have been many attempts to study and predict the hydram operation. The studies can be

divided into three main groups as fo l lows.

Empirical Methods

The method re l ied on experimental tests with resu l ts not supported or correlated by theory.

The empirical formulations were of l imi ted app l i cab i l i t y and sometimes led to some

' ru les-of- thumb' , some of which were misleading. Empirical formulas were insu f f i c ien t for the

prediction of hydram operation because the hydraulic ram operation depends on many var iables,

most of which were neglected in the formulas.

Analyt ical Methods

Using the basic rules of hydraulics and f l u i d mechanics, attempts have been made to

ascertain the rate of change of the variable ve loc i ty of water in the drive pipe during each

phase of the cycle. From these analyses operating character is t ics of the hydram are determined

(Bergeron 1928, Iversen 1975). The methods were not very successful because several parameters

re lat ing to the operation of the hydram are best obtained experimentally. These parameters

include loss of head by f r i c t i on and turbulence through the waste valve, f r i c t i o n loss in the

drive pipe and the del ivery valve. Without these experimentally-determined parameters, the

formulations become very complex and include parameters that are d i f f i c u l t to estimate.

- 73 -

Rational Methods

Methods based on theoret ica l analysis of the hydraulic ram, with some parameters determined

experimentally have been ver i f i ed by Gosline and O'Brien (1933), Lansford and Dugan (1941), Krol

(1951), Kahangire (1984). This is so far the most successful approach to the study of the

operation of the hydraulic ram pump.

ANALYSIS OF THE HYDRAULIC RAN ACTION

ai r c h a m b e r

h e a d e r

^ t a n k

d e l i v e r y v a l v e

Hd

FIGURE 1 : TYPICAL HYDRAULIC RAN INSTALLATION

Hydraulic Ram Action

The momentum produced by a flow of water from a low supply head, H, (Figure 1) i s used to

pump a small part of the flow to a higher head, Hd, above the waste valve opening. The rapid

opening and closing of the waste and delivery valves creates pressure surges which are

superimposed on the major ef fects of steady pressure differences and k inet ic energy of the flow

in the drive pipe. The pressure f luctuat ions create compression waves which, in t u r n , are

superimposed on the veloci ty changes in the drive pipe. Considering a l l these effects would lead

to a very complex analysis. Theoretical models that predict the hydran performance accurately

are therefore lengthy and complex which reduces the i r usefulness to pract ical designers and users

of hydrams.

- 74 -

The approximate analysis presented in th i s paper i s based on the average ef fects of the

supply head, atmospheric pressure, del ivery head and f r i c t i o n a l forces. Only the main ef fects of

the hydram action are considered and the model derived is simple to understand and use. The

major waterhammer ef fects are considered together with the f r i c t i o n head losses. The deta i ls of

reco i l and ef fects of e l as t i c i t y of valve materials are neglected (Kahangire 1984). The analysis

l i es between the detailed analysis of Krol (1951) and the s impl i f ied analysis of Iversen (1975).

Hydram Operation

For th i s simple analysis the pumping cycle of the hydram is divided into four main periods.

The div is ion i s based on the posit ion of the waste valve and the average t ime-veloci ty var iat ion

in the drive pipe (Figure 2) .

TIME(t)

FIGURE 2 : TIME-VELOCITY VARIATION I N THE DRIVE PIPE

A. The waste valve i s open and water s tar ts to flow from the source and escapes through the

waste valve. The flow accelerates under the effect of the supply head, H, u n t i l a ve loc i ty

V i s attained in the drive pipe. At t h i s ve loc i t y , the to ta l drag and pressure forces on

the waste valve equals i t s weight and thereafter the valve begins to c lose.

B. The waste valve continues to close and is f i n a l l y f u l l y closed. For a good hydram design,

the valve closure i s rapid or instantaneous.

C. The waste valve i s f u l l y closed and remains closed. The sudden closure creates a high

pressure in the hydram and on the check valve that i s in excess of the s ta t ic del ivery

pressure. The check valve i s forced open and pumping takes place un t i l the veloc i ty becomes

zero and pumping stops, under the retarding effect of the del ivery pressure head.

- 75 -

D. The delivery valve closes. The pressure near the check valve is much higher than the static

supply pressure and the flow is reversed towards the supply source. This action is termed

recoil. The recoil action creates a vacuum in the hydram, temporarily forcing a small

amount of air to be sucked into the hydram through the air valve. The pressure on the

underside of the waste valve is also reduced and together with the effect of its own weight,

the waste valve opens automatically. The water in the drive pipe returns to the static

supply pressure as before and the next cycle begins. The action is repeated automatically

at a frequency of a few beats to over 300 beats per minute.

THEORETICAL MODEL OF THE HYDRAULIC RAM

At the University of Ottawa, a computerized theoretical model based on the assumed cycle of

operation given in the previous section was developed to assist in deriving the operating

characteristics of any given hydraulic ram pump. The computer program listing was originally

given in Fortran language but has now been converted to Basic language for use on microcomputers.

The development of the model is based on the following assumptions:

1. Approximate one-dimensional steady flow equation is applicable for the flow in the drive

pipe.

2. The friction losses in the drive pipe and pump do not vary with the variation in velocity

but are constant. Therefore, the parameters determined under steady flow conditions are

approximately constant.

3. The waste valve closure is instantaneous.

4. The velocity of water in the drive pipe when the waste valve begins to close and that when

the waste valve is finally close are almost the same.

5. The resistance due to spindle movement through the valve guide is negligible and constant.

6. Only the average flow velocity and pressure difference variations in the system are

considered.

- 76 -

In order to use the derived model, the following paramters need to be obtained (some

experimentally) from the hydram design and i n s t a l l a t i o n . These include: (a) drive pipe length

(L) ; (b) cross-sectional area of the drive pipe; (c) dr ive pipe diameters and thickness; (d)

supply head (H); (e) del ivery head (h ) ; ( f ) f r i c t i o n head loss in the drive pipe alone (XM); (g)

f r i c t i o n losses through the waste valve alone (RS); (h) f r i c t i o n head los at the del ivery valve

(HVD); ( i ) the veloci ty in the drive pipe when the waste valve begins to close (VQ) ; and ( j ) the

steady flow veloc i ty (V8) through the waste valve when f u l l y open.

COMPARISON OF OBSERVED AND COMPUTER MODEL RESULTS

The theoret ical hydram model derived above was tested against experimental resul ts from two

1 i inch (32mm) hydrants, one of which was made loca l l y from ateel pipe f i t t i n g s . Various

experimental test resul ts were done for a supply head of about 2m, stroke lengths between

1mm-12imn and drive pipe length of 15.5m (Kahangire, 1984). for a typ ica l run , V8, M, N, V0, HVD

and XM were determined experimentally under steady flow condit ions. The resul ts presented here

are for the loca l l y made hydram with a valve weight of 0.36N, valve stroke length of 2mm, and

drive pipe length of 15.5m. For th i s test run, the fol lowing parameter values were obtained and

used in the model: VQ = 0.40m/sec; M = 69; N = 69; HVD = 70; and XM = 12. The comparison of the

observed and model resu l ts i s shown in f igures 3, 4, 5 and 6. This pattern of agreement was

observed in the other tests wi th the locally-made hydram and the commercial hydram (Oevey model

4) (Kahangire, 1984).

PRACTICAL ASPECTS OF HYDRAM DESIGN AND INSTALLATION

Eff ic iency

There are two methods commonly used to compute the ef f ic iency of a hydram i n s t a l l a t i o n ; the

Rankine and the D'Aubuiaaon methods, both of which were proposed by Eytelwein (Mead 2933, Calvert

1957). The difference depends on whether the surface elevation of the water source or the waste

valve opening i s taken as the datum.

E (Rankine) = Q.h (1)

Qw.H

E (D'Aubuisson) r Q.Hd (2)

(Q+Qw)H

- 77 -

Where Q i s the pumped flow per minute, Qw i s the wasted flow per minute, h is the pump head above

the source, H i s the supply head above the waste valve opening and Hd i s the to ta l del ivery head

above the waste valve opening (Figure 1) .

For pract ical purposes, i t does not matter which formula i s used. The two equations give

s l i g h t l y d i f fe ren t resul ts and any references to hydram ef f ic iency values should indicate the

method used. The D'Aubuisson formula gives higher values. I t also has the shortcoming of giving

e f f i c iency values even when no useful work i s done by the pump. For f i e l d tests and pract ical

appl icat ions, the Rankine de f i n i t i on of ef f ic iency i s to be preferred.

Some empirical formulas have been suggested based on experimental tes ts . Eytelwein with

data from over 1100 experiments from two d i f fe rent hydrams derived the following equation for

hydram ef f ic iency

E = 1.12 - 0.2 V h (3) "H

(Cleghorne 1919). Another one by D'Aubuisson was of the form

E = 1.42 - 0.28 V ^ d (4) H

(Anderson 1922) where h and H are as defined ea r l i e r . These equations relate to the speci f ic

hydram3 tested. They also indicate the general nature of the ef f ic iency curves for these types

of pumps and show how ef f ic iency reduces as the pump head increases for a given supply head.

Drive Pipe Specif icat ions

The drive pipe i s an important component of the hydram i n s t a l l a t i o n . The drive pipe must be

able to sustain a high waterhammer pressure caused by the closing of the waste valve. I t s

diameter depends on the size of the hydram, strength requirements, cost considerations,

a v a i l a b i l i t y of pipe materials and, in some cases, the available supply f low.

In spi te of several experimental invest igat ions, there i s no agreement as to what length of

the dr ive pipe should be used. The drive pipe length should depend on the supply head and i t s

own diameter. The length commonly used in Europe and North America l ies between the l im i t s

- 78 -

6H<L<12H (Krol 1951). Eytelwein suggested an empirical re lat ionship to determine drive pipe

length

L : h + 0 . 3 l i (5) H

(Weisbach and Herrmann 1897).

Russian researchers derived an empirical formula to determine suitable drive pipe length (L)

as

L = 900 H (6)

where D is the drive pipe diameter and N i s the number o f valve beats per minute. Calvert

experimentally determined the l i m i t s of suitable drive pipe length as

150<_L_<1000 (7) D

Outside these l im i t s the pump wi n t work properly. On the basis of analy t ica l studies, for

the pump to operate continuously and automatically, the drive pipe length (L) should l i e between

the l im i ts

OyKDtCrfAvjH - Wd-t-Eh, + RS)] (8)

(Krol 1951, Kahangire 1984). For pract ical purposes, Calvert 's equation gives better guidelines

since i t takes into account the size of the drive pipe.

Due to the high pressures involved, the drive pipe i s usually made of steel or cast i r o n .

Other materials can be used but w i l l not give as good resu l ts as steel in terms of the del ivery

pressures that the pump w i l l develop. The pipes must also be su f f i c i en t l y th ick (Figure 3) to

withstand the high waterhammer pressures that are generated (Watt 1975).

In a recent study, Kahangire (1984) used a theoret ica l computerized model to invest igate the

effects of drive pipe length on hydram operation. By varying the length between 1 m and 121 m,

the following ef fects were observed: Increasing drive pipe length s l i g h t l y reduced peak pump

ef f ic iency, decreased pumped flow and peak power. Cycle duration was greatly increased by

- 79 -

40-50S. General ly, the length should not be too short as the valve w i l l close very f a s t , often

with no s ign i f i cant increase in water being pumped. I f the length i s very long, the f r i c t i o n

head losses w i l l dominate and reduce the pump c a p a b i l i t y . I f the supply head i s high and the

dr ive pipe i s long, the momentum of water in the dr ive pipe w i l l be very high and the pump w i l l

be damaged. In that case, a stand pipe should be inserted along the drive pipe to reduce the

e f f e c t i v e supply head.

Air Chamber

The e f fect of the a i r chamber size on hydram operation i s not c l e a r l y known. Krol (1951)

noted an increase of 105» in pump ef f ic iency when the a i r chamber volume was doubled. Krol

recommends the a i r volume to be approximately 100 times the volume of water delivered per cyc le .

Cheghorne (1919) recommended the volume to be approximately twice the volume of the v e r t i c a l

height of the de l ivery p ipe . Experiments with a locally-made hydram from pipe f i t t i n g s with a

2- inch (51mm) diameter pipe and lengths between 0.30 m - 1.3 m showed no s igni f icant e f fect of

the a i r chamber volume on the operating character is t ics of the hydram (Kahangire 1984). Inversin

(1978) also found no ef fect of a i r chamber volume on hydram operat ion. Probably for high supply

head a and long dr ive pipes, large a i r chambers and a i r volumes may be necessary to absorb the

increased waterhammer pressures that w i l l occur in the hydram.

Air Valve

This is usually a small hole or a one-way va lve . Experiments with d i f f e ren t sizes indicate

that the s ize has a negl ig ib le ef fect on the hydram operat ion. Only when the hole became so

large that h a l f of the pumped flow was escaping through i t , did the e f fect become noticeable on

hydram e f f i c iency (Figure 4 ) . The pump capaci ty , however, was not a f fec ted . A small hole les3

than 1.0 mm should su f f i ce (Kahangire 1984).

Design o f the Waste Valve

A good waste valve design and proper adjustment are very essential for smooth and e f f i c i e n t

hydram operat ion. The design de ta i l s include proper proportioning of the valve opening or

o r i f i c e area (AQ) and the cross-sectional area ( A y ) , i t s weight (W) and the stroke length (S) of

the waste valve i t s e l f . The mechanism control l ing the valve movement or valve guide should allow

free and smooth movement. I f good qual i ty s tee l i s not ava i lab le , weighted impulse valves are

more sui table than spring-type valves.

- 80 -

Common sizes of the waste valve are less than 4 inches (100 mm) and very few actual ly exceed

3-inch (75 mm). These sizes are considered more e f f i c i e n t while larger sizes are not (Richards

1922). Bergeron (1928) showed a n a l y t i c a l l y that the flow area through the waste valve should

equal or exceed the cross-sectional area of the drive pipe to avoid 'choking' the flow. In most

commercial hydrams, the waste valve area Ay is usually bigger than the size of the i n l e t at the

dr ive pipe-hydrant connection.

Experiments at the University of Ottawa with a locally-made hydrant indicated that there i s a

wide range of combination of AQ and Ay for which the hydrant operation was not af fected for valve

sizes not exceeding 70-758 of the valve 'pot ' or 'housing' diameter (Figure 5 ) . The experiments

also incidated that changing valve stroke had a s imi lar e f fec t as changing the valve weight on

hydrant operat ion. However, increasing valve stroke gave be t te r and a smoother hydran operation

than increasing the weight. In general , increasing valve stroke or weight reduced pump

e f f ic iency (Figure 6) but increased the flow. The head r a t i o - f l o w rat io-curve remained the same

(Figure 7 ) . The e f fect of valve stroke on hydrant operation for well-designed commercial hydrams

may be small . Changing the valve stroke length a l tered the character is t ics of the valve (Figure

8) and the resul ts indicate that hydrant operation may be more stable for stroke lengths greater

than 4 mm. I t was v e r i f i e d with the theoret ica l model that high f r i c t i o n losses through the

waste valve are undesirable as they reduce the pump capacity (Figure 9) and af fect i t s general

operating charac te r is t i cs . To minimize energy losses, the waste valve should be reasonably l i g h t

and adjusted in such a way that i t w i l l close fast . I t was shown a n a l y t i c a l l y that for a given

i n s t a l l a t i o n and valve design and st roke , the valve weight should l i e within the l i m i t s

0 < W < C d A v j H _ (9)

M

Krol (1976) indicated that there i s a re la t ionship between valve stroke (S) and the maximum

weight of the waste va lve , WmaKt that can be used, such that

SHmax = Constant (10)

- 81 -

Del ivery (Check) Valve

Generally, the valve should be such that i t opens f a s t , closes evenly and of fers as l i t t l e

resistance to the flow as posible . As to i t s opening, Anderson (1922) recommends one square inch

(6 .54 sq cm) of area through the valve for every gal lon (4 .5 l i t r e s ) of water to be de l ivered .

Recent experimental studies with del ivery valves made of a perforated plate and covered with a

rubber disc of d i f f e ren t thickness indicated that th in rubbers give high hydram e f f i c ienc ies but

weaken fast and have to be replaced quite o f t e n . The rubber tends to get sucked into the

perforat ions and get cut due to the back pressure from the del ivery pipe and a i r chamber.

Increasing the rubber thickness affected hydram operat ion, pr imar i ly the pump e f f ic iency (Figure

1 0 ) . The theore t ica l model gave correlated resu l ts showing that the head losses through the

de l ivery valve had t h e i r largest ef fect on hydram e f f ic iency (Figure 1 1 ) . For high supply and

del ivery heads, a thicker rubber w i l l be necessary to withstand the back pressure and last long.

In that case, the perforat ions could be enlarged to minimize the f r i c t i o n losses. I t was noted

in the experiment that except for very th ick rubbers (10 mm) the pumped flow was not

s i g n i f i c a n t l y affected (Figure 1 2 ) .

Supply Head

Increasing the supply head increases the ve loc i ty and momentum of water i n the drive pipe.

Inversin (1978) deduced from experimental resu l ts that with the simple weighted impulse valves,

the supply head should not exceed 4 m, otherwise the valve w i l l be closing so rapidly and

frequently that no useful work w i l l be done. In such a case, the valve should be assisted by a

spring to regulate i t s c losure . Experimental resu l ts indicated pump e f f ic iency and pumped flow

increased in d i rect proportion to the increase i n supply head, pa r t i cu la r l y pump flow (Q) . Power

and valve beat frequency also increased. The theore t ica l model using supply heads of 2 m - 6 m

indicated a big increase in peak pump e f f ic iency and pumped flow. The cycle duration was great ly

decreased. Therefore, depending on the waste valve design, stroke length and weight, there i s a

maximum supply head at which the pump w i l l not work properly. There i s also a minimum supply

head necessary to operate the hydram.

Veloci ty of Water i n the Drive Pipe

The most important design parameter i s the ve loc i ty at which the waste begins to c lose, VQ.

Studies with the theore t ica l model (Kahangire 1984) indicated that th is parameter i s the most

important for determining hydram operation (Figure 13 and 1 4 ) . Therefore, any hydram design,

- 82 -

ins ta l la t ion and adjustment conditions that affect the valve of VQ, w i l l dramatically af fect the

general operating character ist ics of the hydram. VQ i s affected by the weight, stroke length,

size and the general design of the waste valve.

CONCLUSION

Many researchers have shown that with some assumptions and parameters determined

empir ica l ly , the performance of the hydraulic ram can be predicted. Kahangire (1984) went

further and demonstrated that the models can be used for preliminary design of hydrams and

invest igat ion of suitable hydram s i t es .

The mechanism of a hydram and i t s simple mechanical design and maintenance requirements make

i t a unique water-pumping machine potent ia l ly sui table for small scale water supply schemes i n

developing countr ies. Only a spring balance, stop watch and a cal ibrated cyl inder or pa i l are

suf f ic ien t to determine factors for the design of a simple e f f i c i en t hydraulic ram pump. The

computer program can also determine i t s performance curves.

Theoretical models can be used to predict hydran performance and can assist in the

preliminary design and survey of possible s i tes for hydram use. The simple model developed has

the capabi l i ty of predict ing the major character is t ics of the hydram wi th in acceptable er rors .

Some more work i s needed to improve on i t s accuracy while s t i l l keeping i t simple.

Information on pract ical hydram sizes and i ns ta l l a t i on l im i ta t ions is often not avai lable.

Such information i s necessary to prevent expensive fa i lures in the f i e l d and arb i t rary hydram

designs and i ns ta l l a t i ons . Computer programs can yield t h i s information. This would lead to

cost-ef fect ive hydram designs and i ns ta l l a t i ons .

- 83 -

LIST OF SYMBOLS

A - c r o s s - s e c t i o n a l area o f the d r i v e p ipe

A0 - area o f the waste valve o r i f i c e

Av - c r o s s - s e c t i o n a l area o f the waste va lve

c - speed or c e l e r i t y o f an acoust ic wave i n water

Cj - d imensionless drag fo rce c o e f f i c i e n t

E - modulus of e l a s t i c i t y o f the d r i ve p ipe ma te r i a l

e - mechanical e f f i c i e n c y o f the pump

f - f r i c t i o n f a c t o r o f the d r i ve pipe

F - drag fo rce on the waste valve

g - a c c e l e r a t i o n due to g r a v i t y

H - supply or d r i v e head above the waste va lve

A H - change i n pressure head due to waterhammer

Hd - t o t a l d e l i v e r y head above the waste va lve

HVD - f r i c t i o n a l head loss f ac to r o f the d e l i v e r y va lve alone

h - pump head

Hi - t o t a l minor losses i n the d r i ve pipe

h r - head loss through the d e l i v e r y va lve du r i ng pumping

h m a x - maximum pressure head the pump can develop

K - b u l k modulus o f e l a s t i c i t y o f water

Kc - composite modulus o f e l a s t i c i t y o f water and p ipe ma te r i a l

L - l eng th o f the d r i v e p ipe

M - t o t a l head loss f a c t o r o f both the d r i v e p ipe and waste va lve

m - velocity ratio = V0/V3

N - t o t a l head loss f a c t o r o f both d r i v e pipe and d e l i v e r y va lve

P - pump power

A p - change i n pressure due to waterhammer

Q - pumped f low r a t e

RS - head loss f a c t o r the waste valve alone

t - t ime i n general

T - t o t a l du ra t i on o f the cyc le o f hydram ope ra t i on

t p - t h i ckness o f the d r i v e pipe

V - v e l o c i t y o f water i n the d r i ve pipe i n genera l

V0 - v e l o c i t y o f water i n the d r i ve pipe when the waste valve begins to c lose

Vg - s teady s t a t e f low v e l o c i t y i n the d r i v e pipe

i

- 84 -

LIST OF STOOLS (continued)

Vm - the velocity of the drive pipe just before complete waste valve closure

A V - change in velocity due to waste valve closure

V - flow volume per period of the cycle

W - maximum weight or spring tension of the waste valve

XM - fractional head loss factor of the drive pipe alone

y - specific weight of water

P - density of water

- 85 -

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FIG.3 DRIVE PIPE SPECIFICATIONS (Watt 1975)

- 86 -

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REFERENCES

Addiaon, H. A t r e a t i s e on App l ied H y d r a u l i c s . London: Chapman and Ha l l L t d . , 1964.

Anderson, E.W. " H y d r a u l i c Rams". I n s t i t u t i o n o f Mechanical Enqineers , Proceedings, V o l . 1 ,

1922. pp 337-335.

Bergeron, L . " B e l i e r s Hydrau l iques" ( T r a n s l a t i o n ) . P a r i s : Dunod, 1928. pp 60-104.

C a l v e r t , N.G. " D r i v e Pipe o f a Hydrau l ic Ram." The Eng ineer , V o l . 206 No. 5370. London:

December, 1985. pp1001.

C a l v e r t , N.G. " H y d r a u l i c Ram as a Suc t ion Pump." The Engineer. London: A p r i l , 1960.

C l a r k , J.W. "Hyd rau l i c Rams, t h e i r P r i n c i p l e s and C o n s t r u c t i o n : A Handbook fo r P r a c t i c a l

Men." London: T.T. B a t s f o r d , Sept. 1907 (2nd E d i t i o n ) .

Cleghorne, W.S.H. "The Hydrau l ic Ram." South A f r i c a n Journal o f I n d u s t r i e s . Feb. 1919. pp

135-142.

Gibson, A.M. Hyd rau l i cs and i t s A p p l i c a t i o n s . London: ( 5 t h E d i t i o n ) 1961.

Hwang, N.H. Fundamentals o f Hydrau l i c Eng ineer ing Sy3tem9. New Jersey: P r e n t i c e - H a l l I n c . ,

Eaglewood C l i f f s . 1981 .

I n v e r s i n , A.R. "Hyd rau l i c Ram fo r T rop ica l C l i m a t e s . " V i t a P u b l i c a t i o n . V i t a , Mt . R a i n i e r ,

Mary land. 1979.

I n v e r s i n , A.R. "The Cons t ruc t ion o f a Hyd rau l i c Ram Pump." Papua New Guinea: South P a c i f i c

Appropr ia te Technology Foundat ion. Feb. 1978.

I v e r s e n , H.W. "An A n a l y s i s o f the Hydrau l i c Ram." Journal o f F l u i d s Eng ineer ing , ASME, No.

75-FE-F, T ransac t ions . New York: ASME, June 1975. pp 191-196.

K i n d e l , E.W. A Hydrau l i c Ram fo r V i l l a g e Use. A V i t a P u b l i c a t i o n . Mt. R a i n i e r , Mary land:

V i t a I n c . 1970.

- 98 -

15. Krol, J. "The Automatic Hydraulic Ram." Proceedings of the Institution of Mechanical

Engineers, Vol. 165. 1952. pp 53-65.

16. Krol, J. "The Automatic Hydraulic Rams: Its Theory and Design." ASME Proceedings. ASME,

January 1977.

17. Kaufman, A.W. "Hydraulic Ram Forces Water to Pump Itself." Popular Science, October 1948.

pp 231-133.

18. Madeley, John. "Ram Pumps End Kenyan Woman's Water Trek." World Water, October 1981.

19. Massey, B.S. Mechanics of Fluids, 13(3rd Edition). London: Van Nostrand Reinhold Co.,

1968.

20. Lansford, W.M. and Dugan, W.G. "An Analytical and Experimental Study of the Hydraulic Ram."

Bulletin No. 326, Vol. 38. University of Illinois Engineering Experimental Station: 1941.

21. Mead, D.W. "The Hydraulic Ram." Hydraulic Machinery. New York: 1933. pp 358-383.

22. Mead, D.W. "The Hydraulic Ram for Use in Public Waterworks Systems". Illinois Society of

Engineers and Surveyors, 11th Annual Report. Illinois: 1896.

23. Mead, D.W. "A Large Hydraulic Ram". The Engineering Record, Vol. 44 No 8. New York: August

1901.

24. Molyneux, F. "The Hydraulic Ram Pump for Rural Water Supply." Journal of Fluid Handling,

October 1960. pp 274-276.

25. Gosline, J.E. and O'Brien, M.P, "The Hydraulic Ram". University of California Publications

in Engineering, Vol. 3, No. 1. University of California Press: Berkeley, California,

1933. pp 1-58.

26. Parker, P.M. "The Hydraulic Ram". The Control of Water as Applied to Irrigation, Power and

Town Water Supply Purposes. London: Routledge, G & Sons Ltd., 1932. pp 843-853.

27. Parmakian, John. Waterhammer Analysis. New York: Dover Publications, Inc. 2nd Edition.

1963.

- 99 -

28. Protzen, E.P. "A proposal for Simple Performance Prediction of the Hydraulic Ram."

(Unpublished Research Results), I ns t i t u te for Production Innovation. Dar Es Salaam,

University of Dar Es Salaam. June 1980.

29. Richards, J . "Hydraulic Rams." New York, Journal of the Association of Engineering

Societ ies, Vol . 10. January 1898. pp 27-50.

30. Rife Hydraulic Engine Mfg. Co. Rife Hydraulic Ram (Owner's guide to i n s t a l l a t i o n ,

operat ion, maintenance and service). New Jersey, 1969.

31. Rife Hydraulic Engine Mfg. Co. Manual of Information: Rife Hydraulic Water Rams, New

Jersey: 1981.

32. Sch i l le r , E.J. "Development of a Locally Made Hydraulic Ram Pump." ENERGEX '82 Conference

Proceedings, Solar Energy Society of Canada. August 1982. pp 503-506.

33. Sch i l le r , E.J. "Renewable Energy Pimping from Rivers and Streams." Water Supply and

Sanitat ion for Developing Countries. Michigan: Ann Arbor Science Publishers, 1982. pp

53-64.

34. S i lver , M i tche l l . Use of Hydraulic Rams i n Nepal. A guide to Manufacturing and

I n s t a l l a t i o n . Kathumandu, Nepal: UNICEF, September 1977.

35. Stevens-Quille, P.O. "An Innovation i n Water Ram Pumps for Domestic and I r r i ga t i on Use."

London, Appropriate Technology, Vol. 5 No. 1 , May 1970.

36. Stevens-Guille, P.D. "How to Make and I ns ta l l a Low-cost Water Ram Pump for Domestic and

I r r i ga t i on Use." Cape Town: Department of Mechanical Engineering, University of Cape Town,

August 1977.

37. Streeter, V.L. and Wyle, E.B. Hydraulic Transients. N.Y.: McGraw H i l l Book Company, 1967.

38. Watt, S.B. A Manual on the Hydraulic Ram for Pumping Water. London, Intermediate

Technology. London, Intermediate Technology L t d . 1975.

39. Weisbach, J . and Herrmann, G. " The Hydraulic Ram." The Mechanics of Pumping Machinery.

London: McMillan, 1897. pp 255-265.

-100-

HYDRAULIC RAMS AS POTENTIAL PUMPING UNITS FOR RURAL WATER SUPPLY SCICMES I N TANZANIA

T.S, A. Mbwette and E. Th . P. Protzen

SUMMARY

This paper presents one o f the many e f fo r ts made by the Faculty o f Enqineerinq and the Ins t i tu te

of Production Innovation of the IIDSM (universi ty of Dar Es Salaam) towards the rea l iza t ion o f the aims

o f the International Water Supply and Sanitation Decade. Special reference i s made to the use o f

hydraulic rams alonq with some simple water treatment methods. Beyond the account of theoret ica l and

pract ica l work done to date in the f i e l d o f water supply, the fol lowinq recommendations are made in

order to enable water enaineers to u t i l i z e the hydraulic ram in the i r future desiqn work:

1) that an external sponsor be iden t i f i ed to help evaluate the presented theoret ica l model to enable

an evaluation o f present designs and, where necessary, make modif icat ions.

2) that tests be made on a typ ica l desiqn. The work can eas i l y be done loca l l y since hydraulic rams

are already produced in Tanzania.

3) that an external sponsor help produce performance charts for the Tanzanian desiqn.

4) that the new desiqn be marketed.

INTRODUCTION

For several years now members o f s ta f f o f the Faculty o f Enqineerinq and the Ins t i tu te o f

Production Innovation at the University of Dar es Salaam have been workinq on simple water treatment

and pumpinq systems. This paper qives a b r i e f summary o f detai led invest iqat ions carr ied out in t h i s

f i e l d . Extensive documentation of these a c t i v i t i e s can be found in references ('•), (*) and ( ) .

Tanzania has known the hydraulic ram for at least f i v e decades, but most o f the many pumps i n i t i a l l y

ins ta l led have now disappeared althouqh the i r s imp l ic i t y of operat ion, the i r r e la t i ve l y neql iq ib le

maintenance requirement and especial ly the fact that these pumps draw the i r motive power from the i r

water source are technical factors which hiqhly favour the i r appl icat ion in remote ru ra l areas.

- 1 0 1 -

The authors both remember very wel l how fascinated they were as chi ldren by the numerous thumpinq

water pumps which could be found alonq many streams and brooks. I t seems a joke that people should now

be workinq on the react ivat ion o f hydraulic ram technoloqy.

A SHORT HISTORY OF THE HYDRAULIC RAH

Invention o f the hydraulic ram i9 credited to an Ehqlishman, Mr. Jbhn Whitehurst, whose f i r s t

machine wa9 ins ta l l ed in a brewery in 1773. The drive valve - tap - was operated manually by a

c h i l d . ( " ) In 1779 Joseph Michael de Mantqolfier developed the 9e l f -ac t inq hydraulic ram. On his

machine i t was found that over a period of time the a i r i n the a i r vessel wa9 gradually absorbed by the

water passing through i t and the working o f the ram was a f fec ted . This problem was solved by the

younger brother o f Mantqolfier who added the sn i f te r valve to keep the vessel supplied with a i r .

Since then, qui te a number o f types o f hydraul ic ram pumps have been put on the world market -

some have disappeared, others are 8 t i l l beinq manufactured. Quite a lo t of work has been invested i n

the theoret ica l approach ( ^ ) , ( 6 ) f (7). I t seems thouqh that to date, the manufacturers and the

theoret ic ians have seldom got down to workinq toqether in an attempt to optimize the performance and

use o f the hydraul ic ram in water supply systems.

APPLICABILITY OF HYDRAULIC RAMS IN MATER SUPPLY SCHEMES

Reqardinq the p o s s i b i l i t y o f introducinq hydraul ic rams into dr inkinq (or small scale i r r i qa t i on )

water supply schemes: as lonq as topoqraphical and hydroloqical requirements are s a t i s f i e d , they can be

used to pump ei ther raw water from a source in to the treatment plant or as a sinqle staqe pump from a

pretreatment unit in to the main treatment f a c i l i t i e s . However, i t i s not very common to use hydraulic

rams for pumping treated water to storaqe tanks because the conventional desiqn would involve wastaqe

of a b ig proportion o f the treated water which would have to pass through the drive valve durinq the

pumping cyc les . I t would only be possible i f the raw water does not need any treatment besides

d is in fec t ion before d i s t r i b u t i o n . In th i s case, d is in fec t ion can be conveniently done in the storaqe

tank i f no contact reservoir i s provided. ( I t must be noted here that rams are avai lable that can

u t i l i z e untreated water to pump clean water.) In essence, t h i s means that hydraulic rams can be very

su i tab ly applied in schemes where the source i s lower than the end user i f the topoqraphy allows water

to be supplied by qravi ty af ter sinqle stage pumpinq through the treatment plant or storaqe tank. A

cross section o f such a system is shown in F iq . 1 below.

-102-

Treatment Plant

Village

Hydraulic ram

F i g . 1 Schematic c ross s e c t i o n o f a v i l l a g e water supply scheme w i t h a h y d r a u l i c ram pump.

HYDRAU.IC RAMS IN SIMPLE TREATMENT PLANTS

In cases where raw water has t o be t r e a t e d or improved to acceptab le l e v e l s be fo re d i s t r i b u t i o n to

consuners , the use o f h y d r a u l i c rams along w i t h sane simple t rea tment or pre t reatment methods can

ensure the r e l i a b i l i t y and appropr ia teness o f the whole scheme i n remote r u r a l a reas . The f l o w c h a r t s

tea. 1 - 4 below g i v e some for t h e o p t i o n s o f s imple t reatment systems fo r raw water pimped by

h y d r a u l i c rams.

1 . Source

Hydram

P l a i n

Sedimentat ion

Tank

Storage

Tank Consumers

-103-

2. Source Hydram

Set t l ing Tank

SSF To Consumere

3. Source Hydram

Plain Sedimentation

Tank HRF

- * To

Consumers

4 . Source Hydrant

HRF X SSF To Consumers

Note: SSF = Slow Sand F i l t e r HRF = Horizontal Roughing F i l t e r

Flow charts 1 throuqh 3 are sui table for raw waters with f a i r l y poor physical qua l i t y and rather

low bacter ia l po l lu t ion levels ( * ) . Flow chart number 4 is sui table even for cases of water with

r e l a t i v e l y poor physical qua l i t y and high bac ter is l po l lu t ion as lonq as the f i l t r a t i o n rates used are

l im i ted to acceptable l e v e l s . ( ' ) ( ' ) I t must however be noted t ha t , i n a l l the four cases considered

here, i t is assumed that the raw water has very few or no foreign chemical pol lutants since the ef fect

o f i ndus t r ia l a c t i v i t i e s on water pol lu t ion is not yet very pronounced in rura l areas o f most

developinq countr ies.

RESEARCH IN PRETREATMENT FOR SLOW SAN) FILTERS IN TANZANIA

Since 1979 and after qet t inq reports o f poor performances o f most o f the Slow Sand F i l t e r s (SSF)

b u i l t i n d i f fe rent parts of Tanzania, the Department o f C iv i l Enqineerinq of the UOSM has been

conducting extensive research into the use o f Horizontal Row Rouqhinq F i l t e rs (HRF) as a pretreatment

o f water enterinq SSFs. To th i s end, the Civ i l Enqineerinq Department f i r s t established that the cause

o f the poor operating condit ion o f the SSF was the extended d i rec t feedinq into the SSF o f raw waters

o f unacceptable qua l i ty ( i . e . with t u rb i d i t y o f more than 50 NTU or suspended so l id concentration of

more than 10mq/l) which resulted in very fast cloqqinq o f the f i l t e r beds. Thereafter, laboratory and

f i e l d tests were carr ied out in order to establ ish the best and simplest biophysical pretreatment

methods. HRF proved to be superior in comparison wi th the other three methods i nves t i qa tedO

(namely, p la in sedimentation, p la in sedimentation aided with lamella se t t l e rs and ve r t i ca l rouqhinq

f i l t e r s ) .

-104-

In 1981, a p i lo t plant of v i l l a g e sca le was constructed in Irinqa in order to carry out lonqterm

f ie ld t e s t s with the HRF-SSr systems there (see Fiq .2) . The research work has proved the technical

s u i t a b i l i t y o f t h i s method in pract ise(^) and at the moment, the Civil Ehqineerinq Department o f IDSM,

in collaboration with the Ministry of Water and Eherqy, Danish International Development Aid (DANIDA),

the Norwegian Aqency for International Developnent (NORAD) aid the International Reference Centre for

Wastes Disposal (IRCWD), i s involved in the las t stage of f i e ld invest igat ions which involves

constructing and monitoring the operation o f a number o f v i l l a g e demonstration schemes in the regions

of Maeya, Rukwa and Iringa in order to gain more experience with t h i s technique of water treatment. In

addit ion, t h i s proqramme wil l enable the assessment o f the technique's acceptabi l i ty and s u i t a b i l i t y

and evaluate commimty participation aspects . NORAD has already started construction o f one such

scheme with hydraulic ram pimps, HRF and SSF in the v i l l a g e o f Kasote in Rukwa reqion. More

information about the research work in HRF - SSF systems carried out at UDSM can be obtained from

references (*) aid (•*).

Fiq.2. The pi lot plant constructed at Irinqa

-105 -

OPTIMAL HYDRAULIC RAH PERFORMANCE

I t is our idea that for every size of hydraulic rams, suppliers should have at hand a set o f

charts that w i l l help engineers to f u l l y u t i l i z e the poss ib i l i t i es o f the pump. This is common

practice for any other type o f pumps (centr i fuqal pumps, plunqer pumps). Only with such charts in hand

can water engineers set out to design good water supply systems with hydraulic rams. To t h i s end,

since 1976 the Department o f Mechanical Engineering o f the Faculty o f Engineering and la ter the

Ins t i t u te of Production Innovation both at the USDM have been analysinq theoret ica l approaches to the

predict ion o f pump operat ion. We have been fol lowing the a c t i v i t i e s o f Jandu Plunbers in Arusha who

are competent bui lders o f hydraulic rams of the Blake type. We are aware of the fact that there i s

s t i l l a l o t o f scope for improvement and that i t i s possible to develop a new generation with yet

better and t r u l y predictable performance, possibly competitive enough for export to neighbouring

countr ies.

EXTERNAL INPUTS REQUIRED FOR A CONTINUATION OF STARTED WORK AT THE UNIVERSITY OF DAR ES SALAAM

Based mainly on two published papers(^)(6) »hich in our view give su f f i c ien t theoret ica l

background to the design engineer for a good opt imizat ion o f dimensions, performance and end use, we

formulated a theoret ica l model in 1980 ( ' ) that to date has reguired only l imi ted refinement. An

evaluation o f the model reguires the use of gui te a powerful computer with a p l o t t e r , both o f which we

do not have.

It i s very easy to bu i ld a working hydraulic ram, but an optimum desiqn with predictable

performance can only be made once the f u l l evaluation o f a theoret ica l model has taken place.

THE THEORETICAL HODEL

For the fo l lowinq development we assume that the reader i s fami l ia r wi th basic hydraulic ram

theory. The symbols used are defined at the end of t h i s paper.

The ent i re period o f a complete cycle o f events i n hydraulic ram operation is composed o f :

a) the period o f acceleration o f the dr ive flow from zero ve loc i ty to the ve loc i ty at which

closure o f the dr ive valve takes place;

-106-

b) the period o f decelerat ion o f the pumped f low from the t ime o f simultaneous openinq o f the

discharge valve with closure of the drive valve u n t i l the pimped flow reaches zero v e l o c i t y ;

c) the period o f decelerat ion o f the reverse flow from the t ime o f simultaneous closure o f the

discharge valve with opening of the drive valve u n t i l the flow reaches zero ve loc i ty to

i n i t i a t e another period a ) .

j)p_ - dz fV2dL = dV dL g ^ 2gD dt g

(0 )

A M OCSC

oavc VALVE

Fig. 3. The Hydraulic Ram Control Fbsitions

Formulatinq t h i s equation s p e c i f i c a l l y for the above-mentioned periods in connection with F i q . 3

and taking vol m e t r i c losses into account one arr ives a t :

-107-

I ) the volime o f water actua l ly pumped during one pumping in terva l

Qp = U _ i n (N » • 1) - Q1 ( i ) Np Kp h_

H

with $ = F/((9qHA) characterizing the load on the drive valve.

I f during the operation o f a hydraulic ram, the de l ivery head, h , i s increased gradual ly, there

comes a point at which the machine w i l l s t i l l operate but not pimp. Under the assumptions of

per fect ly sealing valves t h i s point i s characterized by the equation

J-A_ tn(N j + 1) = Q-| Np Kph.

H

I I ) the volume of water actual ly wasted during one dr ive in te rva l i s :

/ h , 2

Qjj = LA l n ( 1 ) + Q1 - _LA_jg!n (N|fo£gH + 1) ( I I ) Nd 1-Nf N r 2 B

*d

Especially wi th a low dr ive head, H, a hydraulic ram w i l l not operate when a cer ta in de l ivery

head, h, is exceeded. This phenomenon occurs when the volumetric loss, Q^, is greater than or

equal to the reverse f low vol line per cyc le .

-mn-

2 B 1)

III) the time required for the full sequence of events i s :

t = (2L2 )2 [ gHNd I

-1 J_ tanh (Nri$)2

HI _1

h)2 tan (N_

With the aid of values from equations (I) aid (II) the efficiency of the 9ystem from

position (4) Fig. 3 i s calculated by:

= ip.il Qd

H

-109-

Furthermore a qua l i t y c r i t e r i on is defined that allows quick comparisons to be made between

d i f fe rent hydraulic rans operatinq on the sane drive l i ne bore. Hiqh ef f ic iency alone does not

characterize the qood machine; i n addit ion to t h i s , the del ivery f low must be as hiqh as possible, the

drive l ine dimensions and cycle frequency as low as possible.

C=*%. (V) ' L.A

FLRTfCR OEVELOmENTS

With the above theoret ica l model at hand we would see a further development o f the started work to

consist o f f i ve phases

Phase I : An evaluation o f the equations for some standard size hydraulic rams with var ia t ions o f

topoqraphic and qeometric data.

Phase I I ; A judqement o f the present Tanzanian hydraulic rams with the resul t inq evaluation fol lowed,

i f necessary, by a new desiqn.

Phase I I I ; The determination o f head loss coef f i c ien ts o f valves.

Phase IV; An evaluation of the theoret ical model for the f u l l ranoe of Tanzanian hydraulic rans be i t

o f a new desiqn or the already ex is t inq one.

Phase V; Either continued manufacture of the present Jandu model or manufacture of the new desiqn,

marketed with performance char ts .

.../nn

-110-

As already stated above, we are not in the posi t ion to do the evaluation work in Tanzania. We are

f u l l y aware of the fact that th i s involves pure donkey work and we would qladly do i t i f we had the

r iqht computer at our d isposal . How rewardinq the expected resul ts would be, is demonstrated in F iq .

4 to 9 which compare the values o f t f , C, J , •? , v_, V . for two hydraulic rams on a 3-inch dr ive

l ine and a 3-inch del ivery valve. One ram has a 4 1/4 inch the other an 8 1/2 inch dr ive va lve.

Str ik inq is the short drive l ine on the l a t t e r and the substant ia l ly increased performance for points

on the max-2% l i n e . The f iqures are a resul t o f a tedious e f fo r t to proqramme the theoret ica l model

on an electronic calculator and f i n a l l y to plot the resul ts manually. Since the performance of a

hydraulic ram depends on the Reynolds nunber the evaluation for Phase I would have to be undertaken for

say a 3/4 inch and an 8 inch drive pipe by:

- varyinq H from H = 1 m to H = 20 m

- varyinq A_/A from A_/A 1 to Ap/A 1

- varyinq Aj/A from A^/A = 1 to A^/A r 20

and p lo t t inq 7 (L h/H), C(L h/H), f ( I h/H), •? (L h/H), ?p(L h/H), tft (L h/H)

- with L from L = H to L = 1000m

- with _h_ from _h = 1 to _h_ = 100 H H H

- with \ varyinq at any point (L h/H) to maximize e f f i c iency .

The judqement in Phase I I would then allow the sane evaluation to take place in Phase IV with

selected values o f A_/A, A^/A. Whereas, in Phase I any sensible value o f valve loss coef f ic ients would

serve the purpose, true measured values from Phase I I I would be inserted for Phase IV.

. . . /111

- 1 1 1 -

COC IDS IONS

1. From the point o f view o f water supply design, the engineers are only awaiting a hydraulic ram

with established performance data so a8 to conf ident ly incorporate i t i n the i r schemes.

2. The theoret ica l model for hydrant optimization and performance pred ic i t ion i s ready for

evaluation. This evaluation cannot be done in Tanzania for lack o f su f f i c ien t computer capacity.

3. Given a sponsor for the evaluation desiqn work on a new generation o f rams with true performance

data, the work can be undertaken and designs placed at the disposal o f water engineers.

-112-

REFERENCES:

1) "Slow Sand F i l t r a t i o n for Community Water Supply in Developing Countries", A Desiqn and

Construction Manual. Technical paper 1 1 , (1978) . IRC/WHO, The Haque - The Netherlands.

2 ) WEO.IN, M. and M3WETTE, T.S.A. (Ju ly 1982) . "Slow Sand F i l t e r Research Project Report 3".

Research report CWS 82 .3 , Uhiversity of Oar es Salaam - Tanzania.

3) WEGTLIN, M. (July 1980) . "Slow Sand F i l t e r Research Project Report 2" . Research Report CWS 80.2,

Uhiversity of Dar es Salaam - Tanzania.

4 ) M3WETTE, T.S.A. (October 1983) . "horizontal Flow Roiqhinq F i l t e r s for Rural Water Treatment in

Tanzania", M. Sc. Thesis, university of Dar es Salaam - Tanzania.

5) IVERSEN, H.W. (June 1975) . "An Analysis o f the Hydraulic Ram", Journal o f F lu ids Engineering

(Transact of the ASME), pp 191 - 196.

6 ) KROLL, J. ( 1951 ) . "The Automatic Hydraulic Ram", I n s t i t u t i o n o f Mechanical Engineering

Proceedings, tol. 165, No. 64, pp 53 - 73.

7 ) PROTZEN, E.Th.P. "A Proposal for Simple Performance Predic i t ion o f the Hydraulic Ram" Internal

Technical Report Available from I P I , USDM.

8 ) STARMER, C. (MARCH 1981) . "Blake's Hydram or The Rise and Fal l o f the Hydraulic Ram, CME,

pp 19 - 2 1 .

- 1 1 3 -

NOMENCLATURE

A - Cro33-section area of flow in drive pipe

Ap - Cross-section area of delivery valve

Ad - Cross-section area of drive valve

B - Bulk Kidulus of Water

C - Quality Criterion

D - Di meter

f - Friction factor

F - Load on drive valve

q - Gravitational acceleration

h - Delivery head measured from water level in supply reservoir

H - Drive head

ty> - Head l o s s c o e f f i c i e n t o f discharqe valve

Kd - Head loss coefficient drive valve

L - Pipe lenqth, drive pipe lenqth

Np - Combined pump f low head l o s s f a c t o r o f system

Nd - Combined d e l i v e r y flow head l o s s f a c t o r system

Nr - Combined r e v e r s e f low head l o s s f a c t o r system

p - Pressure

Op - Pumped vo lune per c y c l e

Qd - Wasted volume par c y c l e

Q1 - Lost vo lune below d ischarqe va lve

Qt - Total volune per c y c l e

t - Time

V - Average v e l o c i t y

Vp - Pumped vo lune f lowrate

Vt - Total volune f lowrate

* - Force coefficient

/* - Density of Water

7 - Efficiency

«? - Cycle frequency

- 1 1 4 -

LINE FOK 1ft MAXIMUM - 2 %

«* 04

O

CO - -

UNE FOR 7 | MAXIMUM * V .

. 4 J 24'

90 l-

4

Pig, 4 Efficiency of 3" Hydraulic Rams

Drive Line Bore 3"

Delivery Valve Diameter 3"

Drive Head 5B

Ram A Drive Valve Diameter 4.25"

Ram B Drive Valve Diameter 8*50"

-115-

Fig. 5 Quality Criterion of 3" Hydraulic Rams

Drive L±ne Bore 3" Delivery Valve Diameter 3" Drive Head 5m

Ram A Drive Valve Diameter ^••25"

Ram B Drive Valve Diaaeter 8#50"

i/> © i n o if) o i n_i CM I T IS o CM iij Lj_mj

-116-

-117-

« a S * 8 « | IH w o s s e g y BI^

Pig* 7 Frequency of 3" Qydraulle R O M

Drive Libe Bore 3" Delivery Valve Diametfer 3n

Drire H»ad 5n»

Bam JL Drive Valve Diameter 4,25"

Bam B Drive Valve Diaaeter 8.50"

h/

-118-

S f 1 I M ll!i . • B f t

h/H

•Fig* 8 Punp^d Volume flow of 3" Hydraulic Rams

Drive Lifre Bore ' * 3" Delivery Valve Diameter 3n

Drive Head 5B

Ram A Drive Valve Diameter 4#25"

Drive Valve Diameter 8.50"

' I I I I I

S LjnettfJ

h/H

s g ? 8 g~ f m.

- 120 -

HYDRAN WORKSHOP PARTICIPANTS

Tanzania Mr. William A. Baynit

Sociologist

Centre for Agricultural Mechanization and Rural Technology (CAMARTEC)

Box 764

Arusha

Tanzania

Mr. Apollo T. Bwojo

Mechanical Engineer

Water Resources Institute

P.O. Box 35059

Oar Es Salaam

Tanzania

Mr. S.S. Jandu

Jandu Plumbers

P.O. Box 409

Arusha

Tanzania

Mr. A.N. Kaaya

CAMARTEC

Box 764

Arusha

Tanzania

Mr. S.A. Mbwette

Faculty of Engineering

Department of C i v i l Engineering

Box 35131

University of Dar Es Salaam

Tanzania

Mr. L. Msimbe

Research Engineer

Ministry of Water, Energy and Minerals

Box 9153

Dar Es Salaam

Tanzania

Mr. A. Mzee

Chief Maintenance Engineer

Ministry of Water, Energy and Minerals

Box 9153

Dar Es Salaam

Tanzania

Mr. E.M. Ngaiza

Director-Genera1

CAMARTEC

Box 764

Arusha

Tanzania

- 121 -

Mr. E. Th. Protzen

Technical Manager

Institute for Production Innovation

University of Dar Es Salaam

P.O. Box 35075

Dar Es Salaam v

Tanzania

Mr. Alexander Schlusser

CAMARTEC

Arusha

Tanzania

Mr. David Tulapona

CAMARTEC

Arusha

Tanzania

Uganda Mr. Patrick Kahangire

Hydroloqist

Ministry of Lands, Minerals and Water Resources

Box 19

Entebbe

Uganda

Mr. Robert Kilama

Mechanical Engineer

Ministry of Lands, Minerals and Water Resources

Box 19

Entebbe

Uganda

Zaabia Mr. V. Liyanage

Senior Project Engineer

Technology Development and Advisory Unit (TDAU)

Lusaka Campus

The University of Zambia

P.O. Box 32379

Lusaka

Zambia

CANADA Mr. James Chauvin

Program Officer

International Development Research Centre

P.O. Box 8500

Ottawa, Ontario K1G 3H9

Canada

Mr. Alex Redekopp

Senior Program Officer

International Development Research Centre

P.O. Box 8500

Ottawa, Ontar io K1G 3H9

Canada

Dr. E r i c S c h i l l e r

C i v i l Engineer ing Department

U n i v e r s i t y o f Ottawa

Ottawa, Ontar io K1N 9B4

TANZANIA

(cont 'd)